title: Activation of a latent RNAase from yeast by nucleoside triphosphates.
abstract: A latent RNAase activity stimulated by nucleoside triphosphates has been isolated from a yeast chromatin extract, by filtration on Sepharose 6B and hydroxyapatite chromatography. The RNAase was separated from a thermolabile proteic inhibitor on phosphocellulose. When separated from the inhibitor, the RNAase hydrolyses RNA to 5'-mononucleotides. Its activity is retained in the presence of EDTA, and 50% inhibited by 1 mM ATP or CTP. The RNAase is inhibited by the thermolabile component only in the presence of divalent cations. The activity is recovered upon addition of 0.01 mM ATP to the mixture. The Km for ATP is 10 microM. ATP can be replaced by other ribo- or deoxyribonucleoside triphosphates with varying efficiency but not by ADP, AMP or cAMP. These results suggest multiple interactions between the RNAase, a regulatory component, divalent cations and nucleoside triphosphates.
mesh_terms: D000255:Adenosine Triphosphate / Q000494:pharmacology*; D002413:Cations, Divalent; D004789:Enzyme Activation / Q000187:drug effects; D046911:Macromolecular Substances; D009711:Nucleotides / Q000494:pharmacology; D012260:Ribonucleases / Q000302:isolation & purification / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000201:enzymology*; D013329:Structure-Activity Relationship
chemical_list: D002413:Cations, Divalent; D046911:Macromolecular Substances; D009711:Nucleotides; D000255:Adenosine Triphosphate; D012260:Ribonucleases