[Specificity of extracellular alkaline RNAase from Penicillium chrysogenum 152A]

Specificity of chromatographically homogenous extracellular alkaline RNAase from Pen. crysogenum 152A on RNA, synthetic polynucleotides, dinucleosidemonophosphates and nucleoside-2',3'-cyclophosphates is studied. The enzyme is found to release from RNA guanosine-3'-monophosphate and guanosine-2',3'-cyclophosphate only. Guanylic acid is a 3'-terminal nucleotide of oligonucleotides of different length. The enzyme readily hydrolyses poly-I and practically do not splits poly-G. GpN is demonstrated to be a good substrate for the RNase, while G greater than p hydrolyses with a low rate. The RNAase catalyses the synthesis of GpC (47.7 per cent yield) and GpU (38.8 per cent yield). Thus, the RNAase from Pen. chrysogenum 152A is considered to be guanyl-RNAase.