期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1972
卷号：69
期号：11
页码：3312-3316
DOI：10.1073/pnas.69.11.3312
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Diisopropylphosphorofluoridate reacts with trypsinogen and chymotrypsinogen and inhibits the potential activity of both zymogens. The reactions follow pseudo first-order kinetics and proceed approximately four orders of magnitude slower than diisopropylphosphorylation of the corresponding enzymes. Correlation of initial rates of inactivation with incorporation of the reagent indicates that zymogen inactivation results from incorporation of 1 mol of organic phosphate per mol of protein. Peptides isolated from the active-site region of trypsinogen account for more than 60% of the label originally present in the [14C]diisopropylphosphoryl zymogen. It is concluded that loss of activation of trypsinogen is due to alkylphosphorylation of Ser183. It is proposed that reduced reactivity of the zymogen, as compared to the enzyme, primarily reflects inefficient binding of substrates and inhibitors, and that Ser183 of the active site exists in trypsinogen in an activated state.
关键词：zymogen activation ; active site ; serine proteases
