Serine proteinase-catalyzed incorporation of D-amino into model peptides in acetonitrile with low water content.
The reactions were studied of N-acyl-L-amino acid esters with various D-amino acid amides catalyzed by free alpha-chymotrypsin, trypsin and proteinase K in acetonitrile containing 80 or 5 vol. % of water. In the medium with low water content the incorporation of D-amino acid amides into peptides proceeded with satisfactory yield sometimes approaching that of analogous L-L dipeptides. In the media with high water content negligible or low yields of L-D dipeptides were achieved. Synthesis of Boc-L-Trp-D-Phe-NH2 catalyzed by alpha-chymotrypsin was performed at molar ratio L: D = 3 : 2 in acetonitrile with 5 vol.% of water and the dipeptide was isolated in larger quantity. However, synthesis of the peptide bond did not occur at all when diastereomeric dipeptides having D-residue in the N-terminal P1' position were used even in the media with low water content.
Cerovský
V
V
Institute of Organic Chemistry and Biochemistry, Czechoslovak Academy of Sciences, Prague.
D000097:Acetonitriles; D000595:Amino Acid Sequence; D000596:Amino Acids / Q000737:chemistry*; D002384:Catalysis; D010455:Peptides / Q000138:chemical synthesis* / Q000737:chemistry; D012697:Serine Endopeptidases / Q000737:chemistry*; D013237:Stereoisomerism; D013379:Substrate Specificity; D014867:Water
D000097:Acetonitriles; D000596:Amino Acids; D010455:Peptides; D014867:Water; D012697:Serine Endopeptidases; C032159:acetonitrile