title: Ribonucleases from porcine brain. Partial purification and properties.
abstract: 1. An acid ribonuclease was partially purified from an acetone powder of porcine brain. This enzyme was an acidic protein with a molecular weight of aroung 70,000. It acted on yeast RNA optimally at about pH 5.9, yielding only a mixture of 3'-mononucleotides, and therefore appears to be an exonuclease. It did not hydrolyze heat-denatured calf thymus DNA or bis(rho-nitrophenyl) phosphate. It was fairly unstable to heat and acid. 2. An alkaline ribonuclease was partially purified from the same source simultaneously. This enzyme was a basic protein with a molecular weight of 25,000-26,000. It was a pyrimidine-specific endoribonuclease, and acted on yeast RNA optimmally at around pH 7.4. It did not hydrolyze heat-denatured calf thymus DNA or bis(rho-nitrophenyl) phosphate. It was fairly stable to heat and acid.
mesh_terms: D000818:Animals; D001921:Brain / Q000201:enzymology*; D002413:Cations, Divalent; D004355:Drug Stability; D005092:Exonucleases / Q000302:isolation & purification / Q000378:metabolism; D007700:Kinetics; D008970:Molecular Weight; D012260:Ribonucleases / Q000302:isolation & purification / Q000378:metabolism; D013329:Structure-Activity Relationship; D013552:Swine; D013696:Temperature
chemical_list: D002413:Cations, Divalent; D005092:Exonucleases; D012260:Ribonucleases