[Study of splitting dinucleoside monophosphates by Penicillium brevicompactum RNAse]

In studies of splitting of transferase substrates cytidylyl-(3' leeds to 5')-adenosine and adenylyl-(3'leds to to 5')-cytidine by Penicillium brevicompactum RNAase the pH-optimum activity of enzyme has been found to fall within the range of 4.7 +/- 0;1; temperature optimum--within 41 degrees--43 degrees C; adenine-nucleotides, their constituent components and polyphosphates display the properties of competitive inhibitors on splitting substrates and that amino-acid residues (presumably weakly- and strongly-protonated imidasole groups) function in the active site of this enzyme (pK 5.88 +/- 0,1 AND 6.6 +/- 0.1). A comparison of some physico-chemical and kinetic parameters of Penicillium breviocompactum RNAse to those of other nonspecific RNAses of fungi is made.