Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.26.9 (ribonuclease)
 6,589 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A base-specific ribonuclease (RNase) Ru (EC 3.1.27.5) was isolated and purified from Rhizopus niveus in a yield of 17% by the procedures of acetone precipitation, column chromatography on Duolite A-2, DEAE-cellulose, CM-cellulose, and 2'(3')-aminohexyl-5'-UMP-agarose. The enzyme was shown to be homogeneous by polyacrylamide disc electrophoresis. The amino- and carboxyl-terminal amino acids of the enzyme were determined to be an arginine and an aspartic acid, respectively. The enzyme has a base specificity: it released only 3'-UMP from yeast RNA or poly(U) and, in addition, small amounts of 3'-CMP from poly(C).
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PMID:Purification of a base-specific ribonuclease Ru from Rhizopus niveus. 616 47

In this study, we explore the evolution and function of two closely related RNase A ribonucleases from the chicken, Gallus gallus. Separated by approximately 10 kb on chromosome 6, the coding sequences of RNases A-1 and A-2 are diverging under positive selection pressure (dN > dS) but remain similar to one another (81% amino acid identity) and to the mammalian angiogenins. Immunoreactive RNases A-1 and A-2 (both approximately 16 kDa) were detected in peripheral blood granulocytes and bone marrow. Recombinant proteins are ribonucleolytically active (kcat = 2.6 and 0.056 s(-1), respectively), and surprisingly, both interact with human placental ribonuclease inhibitor. RNase A-2, the more cationic (pI 11.0), is both angiogenic and bactericidal; RNase A-1 (pI 10.2) has neither activity. We demonstrated via point mutation of the catalytic His110 that ablation of ribonuclease activity has no impact on the bactericidal activity of RNase A-2. We determined that the divergent domains II (amino acids 71-76) and III (amino acids 89-104) of RNase A-2 are both important for bactericidal activity. Furthermore, we demonstrated that these cationic domains can function as independent bactericidal peptides without the tertiary structure imposed by the RNase A backbone. These results suggest that ribonucleolytic activity may not be a crucial constraint limiting the ongoing evolution of this gene family and that the ribonuclease backbone may be merely serving as a scaffold to support the evolution of novel, nonribonucleolytic proteins.
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PMID:Evolution and function of leukocyte RNase A ribonucleases of the avian species, Gallus gallus. 1680 91