Wang Na, Huang Yi-Bing, Xu Li, Wu Xiao-Xia, Zhang Xue-Zhong
Key Laboratory of Molecular Enzymology and Engineering, Jilin University, Changchun, PR China.
Prep Biochem Biotechnol. 2004 Feb;34(1):45-56. doi: 10.1081/PB-120027112.
Trypsin-catalyzed, kinetically controlled synthesis of a precursor, dipeptide of thymopentin (TP-5), Bz-Arg-Lys-OH (or-OEt) in organic solvents was studied. Bz-Arg-OEt was used as the acyl donor and Lys-OH and Lys-OEt were used as the nucleophiles. Ethanol was selected as the organic solvent from ethanol, methanol, acetonitrile, and ethyl acetate tested under the experimental conditions. As expected, Lys-OEt is not a suitable nucleophile in trypsin-catalyzed reaction, due to its competition with the protective Arg-OEt as acyl donor for the active site of trypsin, while Lys-OH does not have this problem. The optimal reaction condition for the synthesis of Bz-Arg-Lys-OH was set up as 20% Tris-HCl buffer, pH 8.0, 35 degrees C for 6 h with the yield of 52.5%, or for 18-24 h with the yield of about 60%.
研究了在有机溶剂中胰蛋白酶催化、动力学控制合成前体胸腺五肽（TP - 5）的二肽Bz - Arg - Lys - OH（或 - OEt）的过程。使用Bz - Arg - OEt作为酰基供体，Lys - OH和Lys - OEt作为亲核试剂。在实验条件下测试的乙醇、甲醇、乙腈和乙酸乙酯中，选择乙醇作为有机溶剂。正如预期的那样，在胰蛋白酶催化反应中，Lys - OEt不是合适的亲核试剂，因为它与作为酰基供体的保护基团Arg - OEt竞争胰蛋白酶的活性位点，而Lys - OH不存在这个问题。合成Bz - Arg - Lys - OH的最佳反应条件设定为20% Tris - HCl缓冲液，pH 8.0，35℃反应6小时，产率为52.5%，或反应18 - 24小时，产率约为60%。
