- A transferase or phosphodiesterase that catalyzes the hydrolysis of ribonucleic acid. SEE ALSO: r. (pancreatic), r. (Bacillus subtilis). SYN: ribonucleinase.- RNase α an enzyme catalyzing endonucleolytic cleavage of O-methylated RNA yielding 5′-phosphomonoesters.- Escherichia coli RNase I SYN: RNase T2.- RNase II an enzyme cleaving RNA exonucleolytically in the 3′ to 5′ direction, yielding 5′-phosphomononucleotides. SEE ALSO: microbial RNase II.- RNase III an enzyme catalyzing endonucleolytic cleavage of double-stranded RNA, yielding 5′-phosphomonoesters.- RNase P an enzyme catalyzing the endonucleolytic cleavage tRNA precursors to yield 5′-phosphomonoesters.- plant RNase SYN: RNase T2.- RNase T1 a nuclease endonucleolytically cleaving ribonucleic acid s at the 3′-5′ link of a guanosine 3′-phosphate residue, producing oligonucleotides terminating in this nucleotide; a transferase (endonuclease) in the first (cyclizing) step, a phosphodiesterase on the second (hydrolyzing) step. SYN: guanyloribonuclease, RNase N1.- RNase T2 an enzyme endonucleolytically cleaving RNA to 3′-nucleotides with 2′,3′-cyclic nucleotides as intermediates. SYN: Escherichia coli RNase I, microbial RNase II, plant RNase, RNase N2.- RNase U2 an enzyme endonucleolytically cleaving RNA to 3′-phosphomono- and 3′-phosphooligonucleotides ending in adenylate or guanylate residues with 2′,3′-cyclic phosphate intermediates.- yeast RNase an enzyme catalyzing the exonucleolytic cleavage of RNA to yield 3′-phosphomononucleotides. SYN: RNase U4.1. Ribonuclease (Azotobacter agilis); ribonuclease (Proteus mirabilis); an enzyme catalyzing the endonucleolytic cleavage of RNA to yield 2′,3′-cyclic nucleotides. 2. Ribonuclease T1.An enzyme isolated from the pancreas of ruminants that transfers the 3′-phosphate of a pyrimidine ribonucleotide residue in a polynucleotide from the 5′-position of the adjoining nucleotide to the 2′-position of the pyrimidine nucleotide itself (a transferase, endonuclease action), thus breaking the chain and forming a pyrimidine 2′,3′-cyclic phosphate, then (or independently) hydrolyzing this phosphodiester to leave a pyrimidine nucleoside 3′-phosphate residue (phosphodiesterase action); used in cytochemistry to selectively degrade and remove RNA as a control for staining of RNA.
* * *ri·bo·nu·cle·ase .rī-bō-'n(y)ü-klē-.ās, -.āz n an enzyme that catalyzes the hydrolysis of RNA called also RNase
* * *n.an enzyme, located in the lysosome of cells, that splits RNA at specific places in the molecule.
* * *ri·bo·nu·cle·ase (ri″bo-nooґkle-ās) any nuclease (q.v.) specifically catalyzing the cleavage of phosphate ester linkages in ribonucleic acids; the ribonucleases are grouped as those cleaving internal bonds (endoribonucleases) and those cleaving at termini (exoribonucleases).
Medical dictionary. 2011.