Entry |
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Name |
Enterobacter ribonuclease
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Class |
Lyases;
Phosphorus-oxygen lyases;
Phosphorus-oxygen lyases (only sub-subclass identified to date)
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Sysname |
[RNA]-adenosine-cytidine 5'-hydroxy-adenosoine ribonucleotide-3'-[RNA fragment]-lyase (cyclicizing; [RNA fragment]-3'-cytidine-2',3'-cyclophosphate-forming and hydrolysing)
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Reaction(IUBMB) |
RNA containing adenosine-cytidine + H2O = an [RNA fragment]-3'-cytidine-3'-phosphate + a 5'-a hydroxy-adenosine -3'-[RNA fragment] (overall reaction);
(1a) RNA containing adenosine-cytidine = an [RNA fragment]-3'-cytidine-2',3'-cyclophosphate + a 5'-a hydroxy-adenosine -3'-[RNA fragment];
(1b) an [RNA fragment]-3'-cytidine-2',3'-cyclophosphate + H2O = an [RNA fragment]-3'-cytidine-3'-phosphate
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Substrate |
RNA containing adenosine-cytidine;
H2O [CPD: C00001];
[RNA fragment]-3'-cytidine-2',3'-cyclophosphate
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Product |
[RNA fragment]-3'-cytidine-3'-phosphate;
5'-a hydroxy-adenosine -3'-[RNA fragment];
[RNA fragment]-3'-cytidine-2',3'-cyclophosphate
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Comment |
Preference for cleavage at Cp-A bonds. Homopolymers of A, U or G are not hydrolysed. CpG bonds are hydrolysed less well and there is no detectable hydrolysis between two purines or two pyrimidines. The enzyme catalyses a two-stage endonucleolytic cleavage. The first reaction produces 5'-hydroxy-phosphooligonucletides and 3'-phosphooligonucleotides ending a with 2',3'-cyclic phosphodiester, which are released from the enzyme. The enzyme then hydrolyses these cyclic compounds in a second reaction that takes place only when all the susceptible 3',5'-phosphodiester bonds have been cyclised. The second reaction is a reversal of the first reaction using the hydroxyl group of water instead of the 5'-hydroxyl group of ribose. The overall process is that of a phosphorus-oxygen lyase followed by hydrolysis to form the 3'-nucleotides.
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History |
EC 4.6.1.21 created 1978 as EC 3.1.27.6, modified 1981, transferred 2018 to 4.6.1.21
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Orthology |
K01169 | ribonuclease I (enterobacter ribonuclease) |
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Genes |
» show all
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Reference |
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Authors |
Levy CC, Goldman P. |
Title |
Residue specificity of a ribonuclease which hydrolyzes polycytidylic acid. |
Journal |
J Biol Chem 245:3257-62 (1970) |
Reference |
|
Authors |
Marotta CA, Levy CC, Weissman SM, Varricchio F. |
Title |
Preferred sites of digestion of a ribonuclease from Enterobacter sp. in the sequence analysis of Bacillus stearothermophilus 5S ribonucleic acid. |
Journal |
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Other DBs |
ExplorEnz - The Enzyme Database: | 4.6.1.21 |
ExPASy - ENZYME nomenclature database: | 4.6.1.21 |
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LinkDB |
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