[Characteristics of acid ribonuclease from rat thymus chromatin].
Acid ribonuclease, free of nucleases and phosphatases, is isolated from rat thymus chromatin. The pH optimum of the enzyme is 5.0-5.5, optimal concentrations of Na+ and K+ ions are 0.05-0.15 M and 0.05 M respectively, Mg2+ inhibits the enzyme activity. The enzyme hydrolyses poly U, poly AU, cytoplasmic and nuclear RNAs, but does not attack poly A, polyG, polyC, poly A:poly U, native and denatured DNA'S. The enzyme is 3'-endonuclease, it splits the bond between the 5'-carbon atom of adenosine, guanosine and uridine and 3'-phosphate of uridilic residue. Middle length of oligonucleotides after the hydrolysis of cytoplasmic RNA comprises 10 nucleotides. Possible role of the enzyme in the processing of nuclear RNAs is discussed.
D000818:Animals; D002843:Chromatin / Q000201:enzymology*; D004720:Endonucleases / Q000302:isolation & purification / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D009994:Osmolar Concentration; D011131:Polyribonucleotides / Q000378:metabolism; D011188:Potassium / Q000494:pharmacology; D051381:Rats; D012260:Ribonucleases / Q000037:antagonists & inhibitors / Q000302:isolation & purification / Q000378:metabolism*; D012964:Sodium / Q000494:pharmacology; D013329:Structure-Activity Relationship; D013950:Thymus Gland / Q000201:enzymology*
D002843:Chromatin; D011131:Polyribonucleotides; D012964:Sodium; D004720:Endonucleases; D012260:Ribonucleases; D011188:Potassium
Kharakteristika kisloi ribonukleazy khromatina timusa krysy.