反应详情

In all cases, the reaction of L-Ala-NH2 (6) with Z-L-Phe-OBn (1) was slower than Gly-NH2 (5) with Z-L-Phe-OBn (1). Further, after 24 hours, Z-L-Phe-Ala-NH2 (11) was obtained in moderate yield (33-57%) using WT, S166C—SCH2C6H5, —SCH2C6F5, and —SCH2(p-COOH—C6H4) as the catalysts. However, Z-L-Phe-Ala-NH2 (11) was obtained in 88% yield in the case of S166C—SCH2CH2NH3+. Unlike S166C—SCH2CH2NH3+, the use of M222C—SCH2CH2NH3+ did not improve the yield of the dipeptide product as compared to the WT-catalyzed reaction; only a low 22% yield of Z-L-Phe-Ala-NH2 (11) was obtained. This was possibly due to the steric interaction of this residue at the binding site, S1 pocket, with the P1 substrate as mentioned above.