D-amino acids in living higher organisms.
The homochirality of biological amino acids (L-amino acids) and of the RNA/DNA backbone (D-ribose) might have become established before the origin of life. It has been considered that D-amino acids and L-sugars were eliminated on the primitive Earth. Therefore, the presence and function of D-amino acids in living organisms have not been studied except for D-amino acids in the cell walls of microorganisms. However, D-amino acids were recently found in various living higher organisms in the form of free amino acids, peptides, and proteins. Free D-aspartate and D-serine are present and may have important physiological functions in mammals. D-amino acids in peptides are well known as opioid peptides and neuropeptides. In protein, D-aspartate residues increase during aging. This review deals with recent advances in the study of D-amino acids in higher organisms.
Research Reactor Institute, Kyote University Kumatori, Sennan, Osaka, Japan. nfujii@HL.rri.kyoto-u.ac.jp
Noriko
N
Fujii
D000595:Amino Acid Sequence; D000596:Amino Acids; D000818:Animals; D019143:Evolution, Molecular; D006801:Humans; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry; D011506:Proteins / Q000737:chemistry*; D013237:Stereoisomerism
D000596:Amino Acids; D010446:Peptide Fragments; D011506:Proteins