The amino acids synthesized at the beginning of life are D and L type. In the past, it was thought that with the evolution of organisms, D-amino acids were selectively excluded, so that all proteins in organisms were composed of L-amino acids.However, with the progress of science and technology and the development of analytical methods, it has been found that marine animals, invertebrates/vertebrates, algae and seed plants contain a variety of free D-amino acids peptide.

It has been found that the amount of D amino acid peptide synthesis is the largest in microorganisms, and the cytoderm of most bacteria is composed of peptidoglycan composed of alanine and other D-amino acids peptide.

There are proteolytic enzymes in all animals. These enzymes can rapidly degrade proteins and make L-amino acids decomposed and been absorbed. However, they can not degrade peptides which containing D-amino acids .It has been proved that D-type amino acid peptide can resist the degradation of protease.Drug researchers are trying to add the D amino acid to the therapeutic polypeptide molecule to counteract the effect of proteolytic enzymes, so that the drug can last longer in the human body.

The peptide modified with D amino acid peptide will be more stable and have stronger anti protease hydrolysis ability, and retain the same binding characteristics as the original L-type peptide.Due to the important use of D-type amino acids, the method of D amino acid peptide synthesis can be divided into the following categories: asymmetric synthesis; Asymmetric transformation; resolution of raceme.

Asymmetric synthesis is a direct and effective method for the production of D amino acids.Asymmetric synthesis is the reaction in which the substrate molecules react with reagents in the presence of catalysts to obtain different amounts of enantiomers.

Resolution of raceme:Racemates are usually obtained by chemical synthesis or racemization of a single isomer. Chemical synthesis of racemates is relatively simple and low cost, so it has been widely used. According to statistics, about 65% of the unnatural chiral drugs are separated by racemates or intermediates. The resolution methods of racemates mainly include preferential crystallization, chemical resolution, biological resolution, extraction resolution, chromatographic resolution and membrane resolution.

Asymmetric conversion is an advanced technology for the resolution of alpha amino acids in recent years. This method eliminates the racemization step in the classical resolution, avoids the loss of another enantiomer, greatly improves the resolution yield, greatly simplifies the operation, and avoids the precipitation phenomenon caused by the increase of enantiomer concentration in the classical resolution method, and ensures the optical purity.

Compared with the 20 L-type amino acids commonly found in nature, 19 kinds of D-type amino acids often play a special role in the activity and stability of peptides, so they are often used as the most basic peptide sequence modification tools.

Applications of D amino acid peptide synthesis

D-amino acids are mainly used as sweeteners in food industry. D-phenylalanine, D-aspartic acid and D-alanine are important raw materials for the synthesis of sweeteners.

In agricultural application, D-valine can be used to synthesize a new high-efficiency broad-spectrum insecticide and acaricide, which can inhibit the activity of insect enzyme system and play a killing role. The insecticidal activity of D-valine is 5000 times higher than that of common pesticides.

D-amino acids are widely used in medicine. Among them, D-p-hydroxyphenylglycine, D-phenylalanine, D-valine, D-proline and D-alanine are the most widely used.D-p-hydroxyphenylglycine and D-p-phenylglycine are important raw materials for the synthesis of antibiotics ampicillin, ampicillin, Cefalexin and cephalosporin,D-phenylalanine is a key intermediate for the production of a new type of antidiabetic drug nateglinide. Nateglinide is one of the most promising drugs for the treatment of type II diabetes.

D-valine is an important chiral drug material, which is widely used in the synthesis of medicine.D-alanine is also widely used in the field of medicine. In the development of new drugs, D-alanine is mainly used in the following aspects: it can be used in the synthesis of sedatives; it can be used as a diagnostic and therapeutic agent for the prediction of premature birth and childbirth; the synthesis of anti nucleoside drugs, which is helpful to AIDS inhibitors: synthetic anticancer drugs. For clinical treatment of cancer and Alzheimer's disease; synthesis of AIDS inhibitors. As HIV antibody; synthesis of DOTA for early diagnosis of cancer; synthesis of antiviral inhibitors, used as antibodies against HTLV and HIV; synthetic antifungal drugs, mixed with a little in toothpaste, can prevent periodontitis and other gum diseases; synthesis of piperazine derivatives, etc.

Omizzur not only provides a large number of of D-amino acids peptide synthesis, but also provides modification of D-type amino acids in custom peptide synthesis services. For more information, please visit www.omizzur.com