The acai extract comes from acai berry. It is a small round grape like fruit that grows on acai plants in the rain forests of Brazilian Amazon, so it is also called Brazilian acai.
What is Acai Berry?
Acai berry products are very popular nowadays, but its history traces back to a long time ago. The earliest record showed that people who lived in Amazon area used it to cure their open wounds. They also used it to boost their energy level so as to win their battles.
Although acai berry contains lots of nutrition, it is only used among Amazon riverbank area in the past, because it is very delicate and is spoiled within 24 hours of harvesting. Only after we finally find the way to get acai extract, can this “super food” spread all over the world. Though acai berry has so many benefits to us, pure acai extract (also known as acai berry powder) has different nutritional value base on processing method. The best method to get acai berry extract will be freeze dried acai, that which is used in “D'Mirakel”.
So, what makes people crazy for this wonderful fruit?
Benefits of Acai
Acai berries are packed full of vitamins and minerals essential to optimal health and wellness. Not only does this supplement have rich omega content for your heart, but it also provides better quality sleep, has high protein value and it helps normalize cholesterol levels. Statistics show that 100 grams of acai extract contain 52.2 grams of carbohydrates, 8.1 grams of protein, 32.5 grams of fat, and 44.2 grams of fiber. And it is believed that acai berry has 10 times the antioxidant power of red grapes, 30 times the anthocyanins of red wine, and double the antioxidant power of blueberries. Now it is widely used for anti-aging, weight loss, and colon cleanse.
There are many people that like to drink a glass of wine a day to help their heart. While it is proven that a glass a day can strengthen your heart, pure acai berries actually have 33 times more antioxidant power than both red grapes and red wine. This provides you with better energy and stamina, essential amino acid complex, and improved digestion as well!
Pure acai delivers a massive attack on vitality-robbing and cancer-causing free radicals. The antioxidant strength of acai is equal to about "7" servings of fruit! Most berries are a healthy source of natural fiber to cleanse your system and get rid of waste and impurities in your system that can lead to sickness and disease. Acai is great for your digestive system! There is no single food or pill in the market today that can be considered “magic”, but acai is ranked high among the most powerful and beneficial natural sources that support a healthy body and lifestyle.
L-proline is an amino acid that is contained within cartilage. It is considered to be a non-essential nutrient, because the body is capable of creating it on its own within healthy individuals. When individuals do not have special conditions or situations that put them at risk for L-proline deficiency, it is normally not necessary to add supplements.
L-proline is produced by glutamic acid. While the body is capable of producing its own supply of proline, it can also be found in natural food sources of meat.
The Benefits of L-proline have been known about since the early twentieth century. Benefits of L-proline include the healthy maintenance of connective tissue and repairing damage to tissue, skin and muscle. It further contributes to a healthy immune system.
Healthy levels of vitamin C increases the effectiveness of L-proline. One of the most important contributions of L-proline is its relationship to collagen. Collagen is found throughout the body including: skin, blood vessels, tendons, bones, and the eye. Improper production of collagen has been linked to genetic disorders that result in joint and spine problems.
As individuals grow older, their natural levels of L-proline may become diminished, which could possibly account for many of the debilitating bone and joint disorders noted in older individuals. Supplemental use of L-proline may help to restore fluidity to joints.
L-lysine is an essential amino acid that cannot be produced by the body, but is necessary for human health. Amino acids are the building blocks of protein, and because of this you must either eat foods containing L-Lysine or take supplements. Some foods that include this essential amino acid are cheese, certain fish, fenugreek seed, eggs, soybeans and nuts.
Benefits of L-Lysine
L-Lysine provides many benefits to the human body. In fact, it is vital for your whole body to function. This amino acid is necessary for collagen formation. Many don't realize this, but collagen is the most abundant protein in our bodies and makes up our cartilage, tendons, ligaments and bones. L-Lysine is also essential for our bodies to absorb calcium.
Other benefits of this essential amino acid are the support of our skin and skeletal system. People with osteoporosis benefit from the use of L-Lysine greatly. It is also necessary for aiding the production of antibodies, which help support the immune system, and hormone and enzyme production.
Most athletes over use their muscles. This amino acid helps to speed recovery of damage caused by over training. It also plays an important role in hormone production, maintaining nitrogen levels and building muscle protein.
Protecting and nurturing muscle tissue is extremely important when you are involved in bodybuilding or any activity that requires extensive muscle use and endurance. Since L-Lysine is effective in strengthening bone tissue as in the case of osteoporosis, it is also essential for keeping your bones strong and healthy.
What is L-lysine?
Dietary Sources:
Foods rich in protein are good sources of lysine. That includes meat (specifically red meat, pork, and poultry), cheese (particularly parmesan), certain fish (such as cod and sardines), nuts, eggs, soybeans (particularly tofu, isolated soy protein, and defatted soybean flour), spirulina, and fenugreek seed. Brewer's yeast, beans and other legumes, and dairy products also contain lysine. Many nuts also contain lysine along with arginine (lysine counteracts some of the effects of arginine). So if someone is trying to eat a diet rich in lysine to prevent HSV outbreaks, nuts would be a good choice.
L-arginine is a chemical building block called “an amino acid.” It is obtained from the diet and is necessary for the body to make proteins. L-arginine is found in red meat, poultry, fish, and dairy products. It can also be made in a laboratory and used as medicine.
L-arginine is used for heart and blood vessel conditions including congestive heart failure (CHF), chest pain, high blood pressure, and coronary artery disease. L-arginine is also used for recurrent pain in the legs due to blocked arteries (intermittent claudication), decreased mental capacity in the elderly (senile dementia), erectile dysfunction (ED), and male infertility.
Some people use L-arginine for preventing the common cold, improving kidney function after a kidney transplant, high blood pressure during pregnancy (pre-eclampsia), improving athletic performance, boosting the immune system, and preventing inflammation of the digestive tract in premature infants.
L-arginine is used in combination with a number of over-the-counter and prescription medications for various conditions. For example, L-arginine is used along with ibuprofen for migraine headaches; with conventional chemotherapy drugs for treating breast cancer; with other amino acids for treating weight loss in people with AIDS; and with fish oil and other supplements for reducing infections, improving wound healing, and shortening recovery time after surgery.
Some people apply L-arginine to the skin to speed wound healing and for increasing blood flow to cold hands and feet, especially in people with diabetes. It is also used as a cream for sexual problems in both men and women.
How does it work
L-arginine is converted in the body into a chemical called nitric oxide. Nitric oxide causes blood vessels to open wider for improved blood flow. L-arginine also stimulates the release of growth hormone, insulin, and other substances in the body.
L-arginine is defined as a semi-essential amino acid. That sounds a bit odd -- something is either essential or it isn't, right? "Essential" has a slightly different meaning in nutrition. An essential nutrient is one that you must obtain somehow, either through diet or through supplements, because your body can't manufacture it on its own [source: Baggott]. L-arginine is described as semi-essential because usually the body produces enough L-arginine on its own [source: MedlinePlus]. But in some cases, such as trauma or liver disease, people can develop deficiencies, and then an L-arginine supplement is called for.
Your body needs L-arginine to make urea, the waste product that you get rid of when you urinate [source: Mayo Clinic]. Urea is a byproduct created when your body breaks down proteins. Your body needs some nitrogen, but the breakdown of protein creates more than you need. Making urea is a very efficient way for your body to get rid of excess nitrogen [source: WebMD]. L-arginine helps your body regulate its waste and certain chemical balances.
L-arginine helps your body manufacture creatine, a protein that contributes to muscle mass and power. L-arginine also helps the body get rid of creatinine, the waste product associated with this process [source: Mayo Clinic].
The synthesis of collagen, for which vitamin C is essential, proceeds in the body as one of its major manufacturing enterprises. A person who is dying of scurvy stops making this substance, and his body falls apart -- his joints fail, because he can no longer keep the cartilage and tendons strong, his blood vessels break open, his gums ulcerate and his teeth fall out, his immune system deteriorates, and he dies.
Collagen is a protein, one of the thousands of different kinds of proteins in the human body. Most proteins occur in only small amounts: the various enzymes, for example, are so powerful in their ability to cause specific chemical reactions to take place rapidly that only a gram or two or even a few milligrams may be needed in the body. There are a few exceptions. There is a great amount of hemoglobin in red blood cells. There is even more collagen in the skin, bones, teeth, blood vessels, eye, heart, and, in fact, essentially all parts of the body.
Collagen as strong white fibers, stronger than steel wire of the same weight, and as yellow elastic networks (called elastin), usually together with macropolysaccharides, constitutes the connective tissue that holds our bodies together.
Like other proteins, collagen consists of polypeptide chains; the long chains of this fibrous molecule contain about one thousand amino-acid residues, about sixteen thousand atoms. It differs from almost all other proteins in being substantially composed of but two amino acids, glycine and hydroxyproline.
Collagen is a kind of supermolecule, however, in its three-dimensional architecture. The polypeptide chains of the two amino acids, alternating with one another and punctuated by the presence of certain other amino acids, are coiled in a left-handed helix. Three of these helical strands are twisted around on another, like strands of a rope, in a right handed superhelix, to compose the complete molecule.
Understandably, the synthesis of this structure proceeds in steps. While it has been known for half a century (these words written in 1985) that vitamin C is essential to the manufacture of collagen, the process is only now yielding to inquiry. It appears that vitamin C is involved at every step.
First, a three dimensional stranded structure is assembled, with the amino acids glycine and proline as its principal components. This is not yet collagen but its precursor, procollagen. A recent study shows that vitamin C must have an important role in its synthesis. Prolonged exposure of cultures of human connective-tissue cells to ascorbate induced an eight-fold increase in the synthesis of collagen with no increase in the rate of synthesis of other proteins (Murad et al., 1981).
Since the production of procollagen must precede the production of collagen, vitamin C must have a role in this step -- the formation of the polypeptide chains of procollagen -- along with its better understood role in the conversion of procollagen to collagen.
The conversion involves a reaction that substitutes a hydroxyl group, OH, for a hydrogen atom, H, in the proline residues at certain points in the polypeptide chains, converting those residues to hydroxyproline. This hydroxylation reaction secures the chains in the triple helix of collagen. The hydroxylation, next, of the residues of the amino acid lysine, transforming them to hydroxylysine, is then needed to permit the cross-linking of the triple helices into the fibers and networks of the tissues.
These hydroxylation reactions are catalyzed by two different enzymes: prolyl-4-hydroxylase and lysyl-hydroxylase. Vitamin C also serves with them in inducing these reactions. It has recently been shown by Myllyla and his colleagues that, in this service, one molecule of vitamin C is destroyed for each H replaced by OH [Myllyla et al., "Ascorbate is Consumed Stoichiometrically in the Uncoupled Reactions Catalyzed by Prolyl-4-Hydroxylase and Lysyl Hydroxylase. Journal of Biological Chemistry 259:5403-5405. 1984]
We have come upon the two big reasons why we require for good health so much larger amounts of vitamin C than are present in the plants we use as food.
First, there is the bodies continuing need for the synthesis of large amounts of collagen for growth and for replacement of the collagen degraded by daily wear and tear.
Second, vitamin C, in the critical reactions that assemble collagen in the tissues, does not serve merely as a catalyst but is destroyed."
Roger J. Williams NUTRITION AGAINST DISEASE 1971) Pages 85-86
Vitamin C is essential for the building of collagen, the most abundant protein built in our bodies and the major component of connective tissue.[Wolbach, S. B.., and Howe, P. R. �ntercellular substance in experimental scorbutus" Arch. Path., 1:1, 1926] This connective tissue has structural and supportive functions which are indispensable to heart tissues, to blood vessels, --in fact, to all tissues. Collagen is not only the most abundant protein our bodies, it also occurs in larger amounts than all other proteins put together. It cannot be built without vitamin C. No heart or blood vessel or other organ could possibly perform its functions without collagen. No heart or blood vessel can be maintained in healthy condition without vitamin C.
Victims of prison camps who have suffered from vitamin C deficiency have been found to have wide-spread fatty deposits (atherosclerosis) in their arteries. It is quite possible that vitamin C deficiency is directly implicated; it is unlikely that such deposits could have been due to too much fat or cholesterol in diet.
Strong evidence has recently been present that individual needs for vitamin C vary widely, and that some individuals have much higher needs than has hitherto been supposed. While the functioning of vitamin C, except for its role in building collagen, is obscure, it is quite possible that many hearts and blood vessels would be better protected if an abundant environmental supply of this vitamin were available in the circulating fluids that bathe the tissue cells.
Roger J. Williams, Nutrition Against Disease, 1971. Pg 85-86 (paperback)
Collagen is an important protein that exists ubiquitously in the body. It is naturally contained in high amounts in the skin, bone, joint cartilage, blood vessels, tendons, and teeth and occupies one third of total body protein maintaining youthfulness, health and beauty.
As we become old, our body's collagen production reduces which results to wrinkles, joint problems, and arthritis. But, these signs of aging can be treated if not permanently at least the process of the aging can be slowed down if supplement is taken. Most collagen supplements claimed to provide the answers in helping you looking young and feeling young as these supplements replenish the reducing supply of natural collagen in our body.
Take for example collagen peptide. Collagen peptide is gelatine, which is broken down into lower molecules so as to function better in the digestion and absorption process. In addition, at the same time as the molecular collagen or gelatine turns into gel when cooled, which limits the proper amount of compounds and manufacturing, collagen peptide has little chance of turning into gel. This characteristic makes it possible to be utilized in low- sticky drinks and many other processed food, all of which are difficult to take advantage of.
The notable characteristics of collagen peptide are that it can be easily digested and absorbed in our body, easily dissolves in water, slight smell and high transparency, solution is of low stickiness, low allergy component, high moisture retention, one hundred percent low calorie protein made use of as health food, diet food, and the like.
Because of the characteristics of Collagen peptide it is broadly used for: health food and drinks, cosmetics, medication for intestinal sickness, health supplies, and the like.
There is a collagen peptide extracted from fish scales. Fish Collagen Peptide is an enzymatically decomposed product consisting of small peptide molecules in the range of 3,000 and 5,000. Its absorption in the small intestine is superior to other collagen products due to its smaller molecule size, which leads to a more efficient collagen synthesis in different parts of the body such as joint tissue, bone, blood vessels, and skin dermis.
Consequently, this product is used for supplements to lessen the pains and aches due to arthritis, artheriosclerosis, and other signs of aging. Moreover, it is widely used cosmetics to support a smooth, radiant, elastic, and well moisturized skin to slow down the wrinkle formation.
Collagen/ˈkɒlədʒɨn/ is a group of naturally occurring proteins found in animals, especially in the flesh and connective tissues of mammals. It is the main component of connective tissue, and is the most abundant protein in mammals, making up about 25% to 35% of the whole-body protein content. Collagen, in the form of elongated fibrils, is mostly found in fibrous tissues such as tendon, ligament and skin, and is also abundant in cornea, cartilage, bone, blood vessels, the gut, and intervertebral disc. The fibroblast is the most common cell which creates collagen.
What is Collagen?
In muscle tissue, it serves as a major component of the endomysium. Collagen constitutes one to two percent of muscle tissue, and accounts for 6% of the weight of strong, tendinous muscles.[3] Gelatin, which is used in food and industry, is collagen that has been irreversibly hydrolyzed.
Chemistry of Collagen
Collagen is a composed of a triple helix, which generally consists of two identical chains (α1) and an additional chain that differs slightly in its chemical composition (α2 ). The amino acid composition of collagen is atypical for proteins, particularly with respect to its high hydroxyproline content. The most common motifs in the amino acid sequence of collagen are Glycine-Proline-X and Glycine-X-Hydroxyproline, where X is any amino acid other than glycine, proline or hydroxyproline. The average amino acid composition for fish and mammal skin is given.
Synthesis of Collagen
The synthesis of collagen occurs inside and outside of the cell. The formation of collagen which results in fibrillary collagen (most common form) is discussed here. Meshwork collagen, which is often involved in the formation of filtration systems is the other form of collagen. It should be noted that all types of collagens are triple helixes, and the differences lie in the make-up of the alpha peptides created in step 2.
1. Transcription of mRNA: There are approximately 34 genes associated with collagen formation, each coding for a specific mRNA sequence, and typically have the "COL" prefix. The beginning of collagen synthesis begins with turning on genes which are associated with the formation of a particular alpha peptide (typically alpha 1, 2 or 3).
2. Pre-pro-peptide Formation: Once the final mRNA exits from the cell nucleus and enters into the cytoplasm it links with the ribosomal subunits and the process of translation occurs. The early/first part of the new peptide is known as the signal sequence. The signal sequence on the N-terminal of the peptide is recognized by a signal recognition particle on the endoplasmic reticulum, which will be responsible for directing the pre-pro-peptide into the endoplasmic reticulum. Therefore, once the synthesis of new peptide is finished, it goes directly into the endoplasmic reticulum for post-translational processing. Note that it is not known as pre-pro-collagen.
3. Alpha Peptide to Procollagen:Three modifications of the pre-pro-peptide occurs leading to the formation of the alpha peptide. Secondly, the triple helix known as procollagen is formed before being transported in a transport vesicle to the golgi apparatus.
i) The signal peptide on the N-terminal is dissolved, and the molecule is now known as propeptide (not procollagen).
ii) Hydroxylation of lysines and prolines on propeptide by the enzymes prolyl hydroxylase and lysyl hydroxylase (to produce hydroxyproline and hydroxylysine) occurs to aid crosslinking of the alpha peptides. It is this enzymatic step that requires vitamin C as a cofactor. In scurvy, the lack of hydroxylation of prolines and lysines causes a looser triple helix (which is formed by 3 alpha peptides).
iii) Glycosylation occurs by adding either glucose or galactose monomers onto the hydroxy groups that were placed onto lysines, but not on prolines. From here the hydroxylated and glycosylated propeptide twists towards the left very tightly and then three propeptides will form a triple helix. It is important to remember that this molecule, now known as procollagen (not propeptide) is composed of a twisted portion (center) and two loose ends on either end. At this point the procollagen is packaged into a transfer vesicle destined for the golgi apparatus.
4. Golgi Apparatus Modification: In the golgi apparatus, the procollagen goes through one last post-translational modification before being secreted out of the cell. In this step oligosaacharides (not monosaacharides like in step 3) are added, and then the alpha peptide is packaged into a secretory vesicle destined for the extracellular space.
5. Formation of Tropocollagen: Once outside the cell, membrane bound enzymes known as collagen peptidases, remove the "loose ends" of the procollagen molecule. What is left is known as tropocollagen. Defect in this step produces one of the many collagenopathies known as Ehlers-danlos syndrome.This step is absent when synthesizing type IV or meshwork collagen.
6. Formation of the Collagen Fibril: Lysyl oxidase and extracellular enzyme produces the final step in the collagen synthesis pathway. This enzyme acts on lysines and hydroxylysines producing aldehyde groups, which will eventually undergo covalent bonding between tropocollagen molecules. This polymer of tropocollogen is known as a collagen fibril.
Molecular structure
The tropocollagen or collagen molecule is a subunit of larger collagen aggregates such as fibrils. At approximately 300 nm long and 1.5 nm in diameter, it is made up of three polypeptide strands (called alpha peptides, see step 2), each possessing the conformation of a left-handed helix (its name is not to be confused with the commonly occurring alpha helix, a right-handed structure). These three left-handed helices are twisted together into a right-handed coiled coil, a triple helix or "super helix", a cooperative quaternary structure stabilized by numerous hydrogen bonds. With type I collagen and possibly all fibrillar collagens if not all collagens, each triple-helix associates into a right-handed super-super-coil referred to as the collagen microfibril. Each microfibril is interdigitated with its neighboring microfibrils to a degree that might suggest they are individually unstable, although within collagen fibrils, they are so well ordered as to be crystalline.
A distinctive feature of collagen is the regular arrangement of amino acids in each of the three chains of these collagen subunits. The sequence often follows the pattern Gly-Pro-X or Gly-X-Hyp, where X may be any of various other amino acid residues. Proline or hydroxyproline constitute about 1/6 of the total sequence. With glycine accounting for the 1/3 of the sequence, this means approximately half of the collagen sequence is not glycine, proline or hydroxyproline, a fact often missed due to the distraction of the unusual GX1X2 character of collagen alpha-peptides. The high glycine content of collagen is important with respect to stabilization of the collagen helix as this allows the very close association of the collagen fibers within the molecule, facilitating hydrogen bonding and the formation of intermolecular cross-links. This kind of regular repetition and high glycine content is found in only a few other fibrous proteins, such as silk fibroin. About 75-80% of silk is (approximately) -Gly-Ala-Gly-Ala- with 10% serine, and elastin is rich in glycine, proline, and alanine (Ala), whose side group is a small, inert methyl group. Such high glycine and regular repetitions are never found in globular proteins save for very short sections of their sequence. Chemically-reactive side groups are not needed in structural proteins, as they are in enzymes and transport proteins; however, collagen is not quite just a structural protein. Due to its key role in the determination of cell phenotype, cell adhesion, tissue regulation and infrastructure, many sections of its nonproline-rich regions have cell or matrix association / regulation roles. The relatively high content of proline and hydroxyproline rings, with their geometrically constrained carboxyl and (secondary) amino groups, along with the rich abundance of glycine, accounts for the tendency of the individual polypeptide strands to form left-handed helices spontaneously, without any intrachain hydrogen bonding.
Because glycine is the smallest amino acid with no side chain, it plays a unique role in fibrous structural proteins. In collagen, Gly is required at every third position because the assembly of the triple helix puts this residue at the interior (axis) of the helix, where there is no space for a larger side group than glycine’s single hydrogen atom. For the same reason, the rings of the Pro and Hyp must point outward. These two amino acids help stabilize the triple helix—Hyp even more so than Pro; a lower concentration of them is required in animals such as fish, whose body temperatures are lower than most warm-blooded animals. Lower proline and hydroxyproline contents are characteristic of cold-water, but not warm-water fish; the latter tend to have similar proline and hydroxyproline contents to mammals. The lower proline and hydroxproline contents of cold-water fish and other poikilotherm animals leads to their collagen having a lower thermal stability than mammalian collagen. This lower thermal stability means that gelatin derived from fish collagen is not suitable for many Gelatin.
The tropocollagen subunits spontaneously self-assemble, with regularly staggered ends, into even larger arrays in the extracellular spaces of tissues.In the fibrillar collagens, the molecules are staggered from each other by about 67 nm (a unit that is referred to as ‘D’ and changes depending upon the hydration state of the aggregate). Each D-period contains four plus a fraction collagen molecules, because 300 nm divided by 67 nm does not give an integer (the length of the collagen molecule divided by the stagger distance D). Therefore, in each D-period repeat of the microfibril, there is a part containing five molecules in cross-section, called the “overlap”, and a part containing only four molecules, called the "gap". The triple-helices are also arranged in a hexagonal or quasihexagonal array in cross-section, in both the gap and overlap regions.
There is some covalent crosslinking within the triple helices, and a variable amount of covalent crosslinking between tropocollagen helices forming well organized aggregates (such as fibrils). Larger fibrillar bundles are formed with the aid of several different classes of proteins (including different collagen types), glycoproteins and proteoglycans to form the different types of mature tissues from alternate combinations of the same key players. Collagen's insolubility was a barrier to the study of monomeric collagen until it was found that tropocollagen from young animals can be extracted because it is not yet fully crosslinked.
However, advances in microscopy techniques electron microscopy (EM) and atomic force microscopy (AFM)) and X-ray diffraction have enabled researchers to obtain increasingly detailed images of collagen structure in situ. These later advances are particularly important to better understanding the way in which collagen structure affects cell-cell and cell-matrix communication, and how tissues are constructed in growth and repair, and changed in development and disease. For example using AFM –based nanoindentation it has been shown that a single collagen fibril is a heterogeneous material along its axial direction with significantly different mechanical properties in its gap and overlap regions, correlating with its different molecular organizations in these two regions.
Collagen fibrils are semicrystalline aggregates of collagen molecules. Collagen fibers are bundles of fibrils. Collagen fibrils/aggregates are arranged in different combinations and concentrations in various tissues to provide varying tissue properties. In bone, entire collagen triple helices lie in a parallel, staggered array. Forty nm gaps between the ends of the tropocollagen subunits (approximately equal to the gap region) probably serve as nucleation sites for the deposition of long, hard, fine crystals of the mineral component, which is (approximately) hydroxyapatite, Ca10(PO4)6(OH)2 with some phosphate. It is in this way that certain kinds of cartilage turn into bone. Type I collagen gives bone its tensile strength.
Types and associated disorders
Collagen occurs in many places throughout the body. Over 90% of the collagen in the body, however, is of type one.
So far, 28 types of collagen have been identified and described. The five most common types are:
Collagen I: skin, tendon, vascular ligature, organs, bone (main component of the organic part of bone)
Collagen II: cartilage (main component of cartilage)
Collagen III: reticulate (main component of reticular fibers), commonly found alongside type I.
Collagen IV: forms bases of cell basement membrane
Collagen V: cells surfaces, hair and placenta
Collagen-related diseases most commonly arise from genetic defects or nutritional deficiencies that affect the biosynthesis, assembly, postranslational modification, secretion, or other processes involved in normal collagen production.
Synthesis
Amino acids:
Collagen has an unusual amino acid composition and sequence:
Glycine (Gly) is found at almost every third residue
Proline (Pro) makes up about 17% of collagen
Collagen contains two uncommon derivative amino acids not directly inserted during translation. These amino acids are found at specific locations relative to glycine and are modified post-translationally by different enzymes, both of which require vitamin C as a cofactor.
Hydroxyproline (Hyp), derived from proline.
Hydroxylysine (Hyl), derived from lysine (Lys). Depending on the type of collagen, varying numbers of hydroxylysines are glycosylated (mostly having disaccharides attached).
Cortisol stimulates degradation of (skin) collagen into amino acids.
Collagen I formation
Most collagen forms in a similar manner, but the following process is typical for type I:
Inside the cell
Two types of peptide chains are formed during translation on ribosomes along the rough endoplasmic reticulum (RER): alpha-1 and alpha-2 chains. These peptide chains (known as preprocollagen) have registration peptides on each end and a signal peptide.
Polypeptide chains are released into the lumen of the RER.
Signal peptides are cleaved inside the RER and the chains are now known as pro-alpha chains.
Hydroxylation of lysine and proline amino acids occurs inside the lumen. This process is dependent on ascorbic acid (Vitamin C) as a cofactor.
Glycosylation of specific hydroxylysine residues occurs.
Triple helical structure is formed inside the endoplasmic reticulum from each two alpha-1 chains and one alpha-2 chain.
Procollagen is shipped to the Golgi apparatus, where it is packaged and secreted by exocytosis.
Outside the cell
Registration peptides are cleaved and tropocollagen is formed by procollagen peptidase.
Multiple tropocollagen molecules form collagen fibrils, via covalent cross-linking (aldol reaction) by lysyl oxidase which links hydroxylysine and lysine residues. Multiple collagen fibrils form into collagen fibers.
Collagen may be attached to cell membranes via several types of protein, including fibronectin and integrin.
Synthetic pathogenesis
Vitamin C deficiency causes scurvy, a serious and painful disease in which defective collagen prevents the formation of strong connective tissue. Gums deteriorate and bleed, with loss of teeth; skin discolors, and wounds do not heal. Prior to the eighteenth century, this condition was notorious among long duration military, particularly naval, expeditions during which participants were deprived of foods containing Vitamin C.
An autoimmune disease such as lupus erythematosus or rheumatoid arthritis may attack healthy collagen fibers.
Many bacteria and viruses have virulence factors which destroy collagen or interfere with its production.
Characteristics
Collagen is one of the long, fibrous structural proteins whose functions are quite different from those of globular proteins such as enzymes. Tough bundles of collagen called collagen fibers are a major component of the extracellular matrix that supports most tissues and gives cells structure from the outside, but collagen is also found inside certain cells. Collagen has great tensile strength, and is the main component of fascia, cartilage, ligaments, tendons, bone and skin.Along with soft keratin, it is responsible for skin strength and elasticity, and its degradation leads to wrinkles that accompany aging. It strengthens blood vessels and plays a role in tissue development. It is present in the cornea and lens of the eye in crystalline form.
Uses
Collagen has a wide variety of applications, from food to medical. For instance, it is used in cosmetic surgery and burns surgery. Hydrolyzed collagen can play an important role in weight management, as a protein, it can be advantageously used for its satiating power. It is widely used in the form of collagen casings for sausages.
If collagen is sufficiently denatured, e.g. by heating, the three tropocollagen strands separate partially or completely into globular domains, containing a different secondary structure to the normal collagen polyproline II (PPII), e.g. random coils. This process describes the formation of gelatin, which is used in many foods, including flavored gelatin desserts. Besides food, gelatin has been used in pharmaceutical, cosmetic, and photography industries.From a nutritional point of view, collagen and gelatin are a poor-quality sole source of protein since they do not contain all the essential amino acids in the proportions that the human body requires—they are not 'complete proteins' (as defined by food science, not that they are partially structured). Manufacturers of collagen-based dietary supplements claim that their products can improve skin and fingernail quality as well as joint health. However, mainstream scientific research has not shown strong evidence to support these claims. Individuals with problems in these areas are more likely to be suffering from some other underlying condition (such as normal aging, dry skin, arthritis etc.) rather than just a protein deficiency.
From the Greek for glue, kolla, the word collagen means "glue producer" and refers to the early process of boiling the skin and sinews of horses and other animals to obtain glue. Collagen adhesive was used by Egyptians about 4,000 years ago, and Native Americans used it in bows about 1,500 years ago. The oldest glue in the world, carbon-dated as more than 8,000 years old, was found to be collagen—used as a protective lining on rope baskets and embroidered fabrics, and to hold utensils together; also in crisscross decorations on human skulls. Collagen normally converts to gelatin, but survived due to the dry conditions. Animal glues are thermoplastic, softening again upon reheating, and so they are still used in making musical instruments such as fine violins and guitars, which may have to be reopened for repairs—an application incompatible with tough, synthetic plastic adhesives, which are permanent. Animal sinews and skins, including leather, have been used to make useful articles for millennia.
Gelatin-resorcinol-formaldehyde glue (and with formaldehyde replaced by less-toxic pentanedial and ethanedial) has been used to repair experimental incisions in rabbit lungs.
Collagen is one of the body’s key natural resources and a component of skin tissue that can benefit all stages of the wound healing process. When collagen is made available to the wound bed, closure can occur. Wound deterioration, followed sometimes by procedures such as amputation, can thus be avoided.
Throughout the 4 phases of wound healing, collagen performs the following functions in wound healing: • Guiding Function: Collagen fibers serve to guide fibroblasts. Fibroblasts migrate along a connective tissue matrix. • Chemotactic Properties: The large surface area available on collagen fibers can attract fibrogenic cells which help in healing. • Nucleation: Collagen, in the presence of certain neutral salt molecules can act as a nucleating agent causing formation of fibrillar structures. A collagen wound dressing might serve as a guide for orienting new collagen deposition and capillary growth. • Hemostatic properties: Blood platelets interact with the collagen to make a hemostatic plug.
