Dipeptides


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Dipeptides

 

organic substances consisting of two amino acids connected by a peptide bond (—CO—NH—). Optically active, they form crystals of characteristic shape. The isoelectric point, color reactions, and other properties of dipeptides are determined by the amino acids that enter into their composition. Dipeptides are compounds intermediate between polypeptides and amino acids and are formed by the hydrolysis of proteins. Dipeptides consisting of the same L-amino acids but in different order yield isomers, for example, leucyl-alanine and alanyl-leucine. Natural dipeptides, such as carnosine and anserine, are found in animal tissues. A dipeptide molecule can be hydrolyzed by acids, alkalies, or enzymes (dipeptidases) to yield two amino acids.

References in periodicals archive ?
Effect of intramuscular fat content on the meat quality and antioxidative dipeptides of Hanwoo beef.
Carnosine and related dipeptides as quenchers of reactive carbonyl species: from structural studies to therapeutic perspectives.
First, isolated and characterized in 1900 by Gulewitsch, carnosine ([beta]-alanyl-L-hystidine) is a dipeptide, which commonly presents in mammalian tissue, and in particular, in skeletal muscle cells; it is responsible for a variety of activities related to the detoxification of the body from free radical species and the byproducts of membrane lipids peroxidation, but recent studies have shown that this small molecule also has membrane protecting activity, proton buffering capacity, formation of complexes with transition metals, and regulation of macrophage function (6).
Instability index is a measure of protein stability in vitro, calculated by the occurrence of 400 dipeptides in the protein sequence (Guruprasad et al.
32) Both carnosine and anserine are antioxidative histidyl dipeptides and the most abundant antioxidants in meat.
Several dipeptides also resulted in differences in growth patterns between the flhD and fliA mutants and the wild type Yersinia.
EZ:faast LC/MS kits from Phenomenex have been developed for the analysis of more than 60 aliphatic and aromatic amino acids, dipeptides and related compounds in just under 20 minutes.
It preferentially cleaves dipeptides from the amino terminus of peptides with a proline or alanine in the second position.
It is known that substrates containing the dipeptides His-Leu or Gly-Gly in their terminal portions are cleaved by ACE (Yang et al.
Probing the RGD Effect on Carrot Somatic Embryogenesis: Effects of Single Amino Acids and Dipeptides.