Broadening of the substrate tolerance of α-chymotrypsin by using the carbamoylmethyl ester as an acyl donor in kinetically controlled peptide synthesis
In the kinetically controlled approach of peptide synthesis mediated by α-chymotrypsin, the broadening of the protease’s substrate tolerance is achieved by switching the acyldonor from the conventional methyl ester to the carbamoylmethyl ester. Thus, as a typical example, the extremely low coupling efficiency obtained by employing the methyl ester of an inherently poor amino acid substrate, Ala, is
Incorporation of unnatural amino acid derivatives into a peptide bond via an oxime ester catalysed by papain or lipase
作者:Shui-Tein Chen、Chin-Far Tsai、Kung-Tsung Wang
DOI:10.1039/cc9960000165
日期:——
In the presence of an oxime in the reaction solution, papain and lipase P (Pseudomonas from Amano) catalysed the stereoselective transesterification of an N-protected amino acid or peptide ester to form an active (oxime) ester which in turn underwent peptide bond formation with several natural and unnatural amino acid derivatives (proline, N-methylglycine, N-methylalanine, α-methylphenylalanine).
在反应溶液中存在肟的情况下,木瓜蛋白酶和脂肪酶 P(天野假单胞菌)催化 N 保护氨基酸或肽酯的立体选择性酯交换反应,形成活性(肟)酯,活性酯又与几种天然和非天然氨基酸衍生物(脯氨酸、N-甲基甘氨酸、N-甲基丙氨酸、α-甲基苯丙氨酸)形成肽键。
Remarkable effects of donor esters on the α-chymotrypsin-catalyzed couplings of inherently poor amino acid substrates
The extremely low efficiency during the α-chymotrypsin-catalyzed coupling of an inherently poor amino acid substrate, e.g., alanine, using the methyl ester as an acyl donor was significantly improved using esters such as the 2,2,2-trifluoroethyl or carbamoylmethyl ester. The ameliorating effect of the latter ester was especially significant.
The lipase(PPL)-catalyzed peptide synthesis(Z-Phe-Phe-NH2) in aqueous water-miscible organic cosolvents was studied using Z-Phe-OEt as an ester substrate and Phe-NH2 as a nucleophile. It was found that peptide yield increased with an increase of the concentration of DMF. At a higher concentration than 50%(v/v), however, peptide yield decreased rapidly. The optimal pH of an aqueous buffer and concentration