Protease-catalyzed small peptide synthesis in organic media

• Published in: Enzyme and microbial technology 1996-11, Vol.19 (7), p.538-544
• Main Authors: Zhang, Xue-zhong, Wang, Xu, Chen, Songming, Fu, Xueqi, Wu, Xiaoxia, Li, Changhao
• Format: Article
• Language: English
• Subjects: Biological and medical sciences; Biotechnology; Fundamental and applied biological sciences. Psychology; Immobilization of enzymes and other molecules; immobilization supports; Immobilization techniques; Methods. Procedures. Technologies; organic solvents; Small peptide synthesis
• ISSN: 0141-0229; 1879-0909
• DOI: 10.1016/S0141-0229(96)00057-9

Four kinds of supports were used to prepare immobilized papain using different methods: simple absorption on Celite, ionic absorption on CM-cellulose and QAE-Sephadex, and covalent cross-linking on egg white protein. The direct effects of the support on the catalytic properties of the enzyme were examined by studying the dependence of water content, pH, ionic strength, and reaction temperature on the yields of a model dipeptide Boc-Phe-ValOMe in ethyl acetate under thermodynamic control. It was found that the supports with low hydrophilicity demonstrated much higher catalytic activity by the enzyme than those with high hydrophilicity. Egg white protein was the best support with a good yield (94.5%) of the dipeptide. Papain and α-chymotrypsin immobilized on egg white protein were used to synthesize a number of dipeptides with Boc-Phe-XOMe showing different substrate specificity. Alcalase was used in the synthesis of some dipeptides containing hydrophilic amino acids and d-amino acids with reasonable yields.