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：1
页码：115-118
DOI：10.1073/pnas.69.1.115
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Advantage was taken of the reversibility of the first step of ribonuclease-A action to synthesize the dinucleoside phosphorothioate Up(S)C from the crystalline isomer of uridine 2',3'-cyclic phosphorothioate [U[IMG]f1.gif" ALT="p" BORDER="0">(S)] and cytidine. Cyclic phosphorothioate was then reformed from Up(S)C by a nonenzymic reaction known to proceed by an in-line mechanism. The geometry of the enzymic reaction was determined to be in-line by a comparison of the U[IMG]f1.gif" ALT="p" BORDER="0">(S) product with the U[IMG]f1.gif" ALT="p" BORDER="0">(S) originally used. By the principle of microscopic reversibility, the geometry of the first step in the action of ribonuclease-A is shown to be in-line.
