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What is Peptide?
Peptides are short polymers of amino acids linked by peptide bonds. Peptides are distinguished from proteins on the basis of size, and as an arbitrary benchmark can be understood to contain approximately 50 or fewer amino acids. In general, if more than 50 amino acids are involved, the compound is a protein, while shorter chains are called peptides.
Proteins consist of one or more polypeptides arranged in a biologically functional way, often bound to ligands such as coenzymes and cofactors, or to another protein or other macromolecule (DNA, RNA, etc.), or to complex macromolecular assemblies. A peptide bond is a covalent chemical bond (bond formed when atoms share electrons) formed between 2 molecules when the carboxyl (-COOH) group of one molecule reacts with the amino (NH3) group of the other molecule. The shortest peptides are di-peptides, consisting of 2 amino acids joined by a single peptide bond. There can also be tri-peptides, tetra-peptides, penta-peptides, etc. Peptides have an amino end and a carboxyl end. A polypeptide is a single linear chain of amino acids bonded together by peptide bonds.
Amino acids that have been incorporated into peptides are termed "residues" due to the release of either a hydrogen ion from the amine end or a hydroxyl ion from the carboxyl end, or both, as a water molecule is released during formation of each amide bond. All peptides except cyclic peptides have an N-terminal and C-terminal residue at the end of the peptide. There are many, many types of peptides, but for skin care, there are specific peptides that are used widely. The most popular are collagen stimulating peptides, then the copper peptides which are also shown to reduce inflammation. Finally, neuropeptides (which claim to relax facial muscles, therefore reducing the appearance of wrinkles, similar to BOTOX), most popular is called Acetyl Hexapeptide-8 or Argireline.
Let's discuss more on Copper peptide, since this will be our main concern. What is copper peptide and how it was proven to cure skin problems?
Copper peptide GHK-Cu is a naturally occurring copper complex of a glycyl-L-histidyl-L-lysine peptide. Since it has three amino acids it is called tripeptide. The GHK-Cu tripeptide has strong affinity for copper(II) and was first isolated from human plasma. It can be found also in saliva and urine.Copper peptides are naturally occurring small protein fragments that have high affinity to copper ions. In human plasma, the level of GHK-Cu is about 200 µg/ml at age 20. By the age of 60, the level drops to 80 µg/ml. In humans, tripeptide GHK-Cu can promote activation of wound healing, attraction of immune cells, antioxidant and anti-inflammatory effects, stimulation of collagen and glycosaminoglycan synthesis in skin fibroblasts and promotion of blood vessels growth. Recent studies revealed its ability to modulate expression of a large number of human genes, generally reversing gene expression to a healthier state. Synthetic GHK-Cu is used in cosmetics as a reparative and anti-aging ingredient.
Dermatologists and other medical professionals have long recognized the potential benefits of copper--in small quantities--for skin and hair care. However, it wasn’t until the 1970s that biochemist Loren Pickart discovered that copper peptides could deliver the benefits of the mineral without risk of exposure to hazardous levels of copper, according to Copper.org.
Although copper peptides are used most widely today to improve the appearance of aging skin, Loren Pickart’s original findings in the 1970s focused on their ability to regenerate tissue in cases where skin had been scarred or damaged, as in a burn or as a result of other medical conditions, such as acne and diabetes-related wounds.
The scars characteristic of such damage are made up of “extra-large” clumps of collagen. Pickart discovered that copper peptides helped to break down this scar tissue and replace it with the “smaller or more regular collagen found in normal skin.” The peptides also stimulate the production of other components essential to healthy skin, including elastin, glycosaminoglycans and proteoglycans.
Here we can understand that copper peptide can treat many skin problems, not only that it has different benefits for a human body.
In the late 1980s, copper peptide GHK-Cu started attracting attention as a promising wound healing agent. Pioneers in this field were J.P Borel and F. Maquart from Université de Reims Champagne-Ardenne (France). At optimal, picomolar to nanomolar concentrations, GHK-Cu stimulated the synthesis of collagen in skin fibroblasts, increased accumulation of total proteins, glycosaminoglycans (in a biphasic curve)and DNA in the dermal wounds in rats. They also found out that the GHK sequence is present in collagen and suggested that the GHK peptide is released after tissue injury. They proposed a class of emergency response molecules which are released from the extracellular matrix at the site of an injury. GHK-Cu also increased synthesis of decorin – a small proteoglycan involved in the regulation of collagen synthesis, wound healing regulation and anti-tumor defense.
The same group established that GHK-Cu stimulated both the synthesis of metalloproteinases, the enzymes which break down dermal proteins, and their inhibitors (anti-proteases). The fact that GHK-Cu not only stimulates the production of dermal components, but also regulates their breakdown suggests that it should be used with caution.
In 2009, a group of researchers from the Seoul National University (Republic of Korea) demonstrated that the copper-peptide GHK-Cu stimulated proliferation of keratinocytes and increased expression of integrins and p63 protein in the epidermal stem cells. Since p63 is considered to be an important marker of stem cell and anti-senescence protein, the authors concluded that GHK-copper is able to recover epidermal stem cells and increase their ability to repair tissue.