Abstract
Uridine 2′,3′-cyclic phosphonate (I) is slowly hydrolyzed by ribonuclease-A with k2 and Km values at pH6 that are respectively 1900 and 15 times smaller than the same parameters at the same pH for the related phosphate (II). Since the ratio of rate constants for hydroxide ion catalyzed hydrolysis is about 4, this result is consistent with, but does not prove a mechanism for the enzymic reaction that requires a pseudorotation.
Full text
PDF






Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- ALBERTY R. A. Enzyme kinetics. Adv Enzymol Relat Subj Biochem. 1956;17:1–64. doi: 10.1002/9780470122624.ch1. [DOI] [PubMed] [Google Scholar]
- Anderson D. G., Hammes G. G., Walz F. G., Jr Binding of phosphate ligands to ribonuclease A. Biochemistry. 1968 May;7(5):1637–1645. doi: 10.1021/bi00845a004. [DOI] [PubMed] [Google Scholar]
- Eckstein F. Uridine 2',3'-O,O-cyclophosphorothioate as substrate for pancreatic ribonuclease (I). FEBS Lett. 1968 Dec;2(2):85–86. doi: 10.1016/0014-5793(68)80108-5. [DOI] [PubMed] [Google Scholar]
- Erman J. E., Hammes G. G. Relaxation spectra of ribonuclease. IV. The interaction of ribonuclease with cytidine 2':3'-cyclic phosphate. J Am Chem Soc. 1966 Dec 5;88(23):5607–5614. doi: 10.1021/ja00975a046. [DOI] [PubMed] [Google Scholar]
- Gassen H. G., Witzel H. Zum Mechanismus der Ribonuclease-Reaktion. 1. Die Aufgabe der Pyrimidinbase bei der Reaktion. Eur J Biochem. 1967 Mar;1(1):36–45. doi: 10.1111/j.1432-1033.1967.tb00041.x. [DOI] [PubMed] [Google Scholar]
- HERRIES D. G., MATHIAS A. P., RABIN B. R. The active site and mechanism of action of bovine pancreatic ribonuclease. 3. The pH-dependence of the kinetic parameters for the hydrolysis of cytidine 2',3'-phosphate. Biochem J. 1962 Oct;85:127–134. doi: 10.1042/bj0850127. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Roberts G. C., Dennis E. A., Meadows D. H., Cohen J. S., Jardetzky O. The mechanism of action of ribonuclease. Proc Natl Acad Sci U S A. 1969 Apr;62(4):1151–1158. doi: 10.1073/pnas.62.4.1151. [DOI] [PMC free article] [PubMed] [Google Scholar]
- SCHERAGA H. A., RUPLEY J. A. Structure and function of ribonuclease. Adv Enzymol Relat Subj Biochem. 1962;24:161–261. doi: 10.1002/9780470124888.ch4. [DOI] [PubMed] [Google Scholar]
- Usher D. A. On the mechanism of ribonuclease action. Proc Natl Acad Sci U S A. 1969 Mar;62(3):661–667. doi: 10.1073/pnas.62.3.661. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Ward D. C., Fuller W., Reich E. Stereochemical analysis of the specificity of pancreatic RNAse with polyformycin as substrate: differentiation of the transphosphorylation and hydrolysis reactions. Proc Natl Acad Sci U S A. 1969 Feb;62(2):581–588. doi: 10.1073/pnas.62.2.581. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Wyckoff H. W., Hardman K. D., Allewell N. M., Inagami T., Johnson L. N., Richards F. M. The structure of ribonuclease-S at 3.5 A resolution. J Biol Chem. 1967 Sep 10;242(17):3984–3988. [PubMed] [Google Scholar]
