[Extracellular RNAase Pch2 of Penicillium chrysogenum 152A: purification, specificity and physico-chemical properties].

Acid RNAase Pch2 was isolated from a filtrate of the cultural fluid of the fungus Penicillium chrysogenum 152A and purified to homogeneity. An analysis of RNAase Pch2 action on RNA and synthetic substrates showed that the enzyme can be attributed to non-specific true ribonucleases (ribonucleate-3'-oligo-nucleotide hydrolase, EC 3.1.4.23). The maximal effect of the enzyme on RNA is observe at pH 4.5 and 55 degree. The RNAase Pch2 is not activated by bivalent metal ions, p-chloromercurybenzoate or beta-mercaptoethanol and is reversibly inactivated by 8 M urea. The enzyme molecule consists of 332 amino acid residues; its molecular weight is 36160, the isoelectric point lies at 5.2.