title: A protease from rat intestine.
abstract: Partially purified ribonuclease H from rat liver nuclei can be inactivated by a soluble fraction from rat intestine; this inactivation is restored by adding trypsin inhibitor, suggesting that the factor is a protease. A preparation has been isolated and purified to homogeneity. The molecular weight of the enzyme was estimated as 28 000 with an optimum pH of 8.0 and an isoelectric point at pH 4.5--4.7. The inactivating and proteolytic activities were observed in parallel throughout the purification procedures. Diisopropylphosphorofluoridate inhibited the protease activity. The protease inactivates deoxyribonuclease I, pyruvate kinase, and aldolase. From experiments with protease modifiers, it seems to be a serine protease of a trypsin-like nature.
mesh_terms: D000818:Animals; D004720:Endonucleases / Q000037:antagonists & inhibitors*; D010450:Endopeptidases / Q000302:isolation & purification* / Q000378:metabolism; D007422:Intestines / Q000201:enzymology*; D008297:Male; D008970:Molecular Weight; D051381:Rats; D016914:Ribonuclease H; D012260:Ribonucleases / Q000037:antagonists & inhibitors*; D012697:Serine Endopeptidases; D013379:Substrate Specificity; D014018:Tissue Distribution
chemical_list: D004720:Endonucleases; D012260:Ribonucleases; D016914:Ribonuclease H; D010450:Endopeptidases; D012697:Serine Endopeptidases