Cerovský V
Institute of Organic Chemistry and Biochemistry, Czechoslovak Academy of Sciences, Prague.
Biomed Biochim Acta. 1991;50(10-11):S44-9.
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.
研究了在含有80%或5%体积水的乙腈中，游离α-胰凝乳蛋白酶、胰蛋白酶和蛋白酶K催化下，N-酰基-L-氨基酸酯与各种D-氨基酸酰胺的反应。在低含水量的介质中，D-氨基酸酰胺掺入肽中的产率令人满意，有时接近类似的L-L二肽的产率。在高含水量的介质中，L-D二肽的产率可忽略不计或很低。在含5%体积水的乙腈中，α-胰凝乳蛋白酶催化下以L:D = 3:2的摩尔比合成了Boc-L-Trp-D-Phe-NH2，并大量分离出二肽。然而，即使在低含水量的介质中，当使用在N端P1'位置具有D-残基的非对映体二肽时，肽键的合成根本不会发生。
