On the mechanism of action of ribonucleases: dinucleotide cleavage catalyzed by imidazole and Zn2+.
- 1 March 1989
- journal article
- research article
- Published by Proceedings of the National Academy of Sciences in Proceedings of the National Academy of Sciences
- Vol. 86 (6) , 1746-1750
- https://doi.org/10.1073/pnas.86.6.1746
Abstract
Cyclization/cleavage of the 2-(p-nitrophenyl) phosphate ester of propylene glycol is catalyzed by imidazole and, much more effectively, by Zn2+ with imidazole. In the latter case, the mechanism involves simultaneous Lewis acid/base catalysis. Similar Zn2+ and imidazole catalysis of cyclization/cleavage is seen with the dinucleotide 3'', 5''-UpU (uridylyluridine). Again, the zinc system is much more effective than is catalysis by imidazole alone, and in this case simultaneous Lewis acid/base catalysis substitutes for the sequential proton acid/base catalysis seen with polynucleotides or dinucleotides and imidazole buffer catalysts. A mechanism is proposed for catalysis of RNA cleavage by the enzyme ribonuclease A, and the relationship of that mechanism to the action of the enzyme model systems is discussed.Keywords
This publication has 6 references indexed in Scilit:
- Charge description of base-catalyzed alcoholysis of aryl phosphodiesters: a ribonuclease modelJournal of the American Chemical Society, 1988
- Sequential general base-acid catalysis in the hydrolysis of RNA by imidazoleJournal of the American Chemical Society, 1986
- An assay to determine the kinetics of RNA cleavageAnalytical Biochemistry, 1985
- Models for metal binding sites in zinc enzymes. Syntheses of tris[4(5)-imidazolyl]carbinol (4-TIC), tris(2-imidazolyl)carbinol (2-TIC), and related ligands, and studies on metal complex binding constants and spectraJournal of the American Chemical Society, 1978
- Catalysis by imidazolium ion and metal ions in the reaction of a phosphate diesterBioorganic Chemistry, 1976
- Interaction of metal ions with nucleic acid and related compounds. XVI. Specific cleavage effects in the depolymerization of ribonucleic acids by zinc(II) ionsBiochemistry, 1971