Peptides are compounds formed when alpha amino acids are linked together by peptide bonds. The compound derived by two amino acid residues is called dipeptide, and in the same way there are tripeptide, tetrapeptide, pentapeptide, etc. Polypeptides usually consist of 10~100 amino acid molecules, which are connected in the same way as proteins, with relative molecular mass below 10,000Da. Peptides are currently widely applied in pharmaceuticals, foods, agriculture and cosmetics.
Peptides are composed of different types and numbers of amino acids, and each peptide has a unique composition structure, which in turn determines and gives rise to different functions. Peptides are the most complex class of compounds in terms of types and functions. Peptides are noted for faster absorption with low or no energy consumption and unsaturability compared to amino acids.
Marketed peptide drugs have been quite widely implemented in treating diseases, including diabetes, cancer, osteoporosis, multiple sclerosis, HIV infection. This field has emerged many blockbuster drugs. These include the GLP-1 receptor agonists Exenatide and Liraglutide for the treatment of diabetes, and the gonadotropin-releasing hormone analogs (GnRHa) Leuprolide and Goserelin for the treatment of cancer. Long-acting, non-injectable formulation will be the focus of research and development in the future.
Peptides showing remarkable characteristics of processing stability, moisturizing property, low viscosity and foaming property endow their extensively applications in food industry. Moreover, they have the advantages of abundant sources, functional diversity and high bioavailability making their applications in functional foods and dietary supplements. Pea peptides are with more nutrients containing 8 essential amino acids required by human body, high water retention, gel formation and good emulsion stability, thus are used as an excellent additive in meat products processing. Due to its foaming properties and other properties, it can be added to pastry products instead of eggs and to noodle products to improve the nutritional value, strength and tenderness of noodles, and the appearance and taste of food.
As plant protectants, peptides can activate plant growth potential, regulate plant metabolism, enhance plant water and fertilizer absorption, promote plant flower bud differentiation, improve crop fruit quality and induce plant resistance to fungal diseases, bacterial diseases, viral diseases and other diseases after being applied on the plant surface. Besides, peptides can be developed into plant immune inducers, fungicides, insecticides and chelated micronutrients, etc.
Peptides are showing huge potential in cosmetic industry, exerting multiple functions as skin tightening，rapid wrinkle repair，muscle relaxation and skin comfort，etc. Argireline, also known as acetyl hexapeptide-3 has the main effect of reducing the wrinkles caused by the contraction of facial expression muscles and wrinkles around the forehead or eyes. Besides, it can promote collagen production, which helps to rebuild skin tissue. Palmitoyl tripeptide-5 is a nutritional anti-wrinkle ingredient used by many famous international cosmetic brands. It helps to improve facial elasticity, reduce facial wrinkles, improve skin water content, and enhance skin radiance, etc.