Pancreatic ribonuclease family (, 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-assocd. glycoproteins, ribonucleate 3'-pyrimidino-oligonucleotidohydrolase) is a superfamily of pyrimidine-specific endonucleases found in high quantity in the pancreas of certain mammals and of some reptiles.
Specifically, the enzymes are involved in endonucleolytic cleavage of 3'-phosphomononucleotides and 3'-phosphooligonucleotides ending in C-P or U-P with 2',3'-cyclic phosphate intermediates. Ribonuclease can unwind the RNA helix by complexing with single-stranded RNA; the complex arises by an extended multi-site cation-anion interaction between lysine and arginine residues of the enzyme and phosphate groups of the nucleotides.
Notable family members
Other proteins belonging to the pancreatic ribonuclease superfamily include: bovine seminal vesicle and brain ribonucleases; kidney non-secretory ribonucleases; liver-type ribonucleases; angiogenin, which induces vascularisation of normal and malignant tissues; eosinophil cationic protein, a cytotoxin and helminthotoxin with ribonuclease activity; and frog liver ribonuclease and frog sialic acid-binding lectin. The sequence of pancreatic ribonucleases contains four conserved and three amino acid residues involved in the catalytic activity.
Human genes
- Angiogenin,
- RNASE1, RNASE10, RNASE12, RNASE2, RNASE3, RNASE4, RNASE6, RNASE7, and RNASE8.
Cytotoxicity
Two pancreatic ribonucleases isolated from the oocytes of the Northern leopard frog - amphinase and ranpirnase - are not inhibited by RI and show differential cytotoxicity against tumor cells. Ranpirnase was studied in a Phase III clinical trial as a treatment candidate for mesothelioma, but the trial did not demonstrate statistical significance against primary endpoints.
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