IUBMB Enzyme Nomenclature


Accepted name: pancreatic ribonuclease

Reaction: (1) an [RNA] containing cytidine + H2O = an [RNA]-3'-cytidine-3'-phosphate + a 5'-hydroxy-ribonucleotide-3'-[RNA] (overall reaction)
(1a) an [RNA] containing cytidine = an [RNA]-3'-cytidine-2',3'-cyclophosphate + a 5'-hydroxy-ribonucleotide-3'-[RNA]
(1b) an [RNA]-3'-cytidine-2',3'-cyclophosphate + H2O = an [RNA]-3'-cytidine-3'-phosphate
(2) an [RNA] containing uridine + H2O = an [RNA]-3'-uridine-3'-phosphate + a 5'-hydroxy-ribonucleotide-3'-[RNA]
(2a) an [RNA] containing uridine = an [RNA]-3'-uridine-2',3'-cyclophosphate + a 5'-hydroxy-ribonucleotide-3'-[RNA]
(1b) an [RNA]-3'-uridine-2',3'-cyclophosphate + H2O = an [RNA]-3'-uridine-3'-phosphate

Other name(s): RNase; RNase I; RNase A; pancreatic RNase; ribonuclease I; endoribonuclease I; ribonucleic phosphatase; alkaline ribonuclease; ribonuclease; gene S glycoproteins; Ceratitis capitata alkaline ribonuclease; SLSG glycoproteins; gene S locus-specific glycoproteins; S-genotype-asssocd. glycoproteins; ribonucleate 3'-pyrimidino-oligonucleotidohydrolase

Systematic name: RNA lyase ([RNA]-3'-cytidine/uridine-3'-phosphate and 5'-hydroxy-ribonucleotide-3'-[RNA] producing)

Comments: Specifically cleaves at the 3'-side of pyrimidine (uracil or cytosine) phosphate bonds in RNA. The reaction takes place in two steps, with the 2',3'-cyclic phosphodiester intermediates released from the enzyme at the completion of the first step. Hydrolysis of these cyclic compounds occurs at a much slower rate through a reversal of the first step, in which the -OH group of water substitutes for the 2'-OH group of the ribose used in the first step, and does not take place until essentially all the susceptible 3',5'-phosphodiester bonds have been cyclised. The enzyme can act as an endo- or exo ribonuclease.

Links to other databases: BRENDA, EXPASY, GTD, KEGG, MetaCyc, CAS registry number:


1. Anfinsen, C.B. and White, F.H., Jr. The ribonucleases: occurrence, structure, and properties. In: Boyer, P.D., Lardy, H. and Myrbäck, K. (Eds), The Enzymes, 2ndedn, vol.5, Academic Press, New York, 1961, pp. 95-122.

2. Beard, J.R. and Razzell, W.E. Purification of alkaline ribonuclease II from mitochondrial and soluble fractions of liver. J. Biol. Chem. 239 (1964) 4186-4193. [PMID: 14247667]

3. Cannistraro, V.J. and Kennell, D. Purification and characterization of ribonuclease M and mRNA degradation in Escherichia coli. Int. J. Biochem. 181 (1989) 363-370. [PMID: 2653829]

4. Cuchillo, C.M., Pares, X., Guasch, A., Barman, T., Travers, F. and Nogues, M.V. The role of 2',3'-cyclic phosphodiesters in the bovine pancreatic ribonuclease A catalysed cleavage of RNA: intermediates or products. FEBS Lett. 333 (1993) 207-210. [PMID: 7693511]

5. Loverix, S., Laus, G., Martins, J.C., Wyns, L. and Steyaert, J. Reconsidering the energetics of ribonuclease catalysed RNA hydrolysis. Eur. J. Biochem. 257 (1998) 286-290. [PMID: 9799130]

[EC created 1972 as EC, transferred 1978 to EC, modified 1981, transferred 2018 to EC]

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