A new ribonuclease from the black oyster mushroom Pleurotus ostreatus.

A ribonuclease that is co-specific for poly C and poly U has been isolated from the fruiting bodies of the black oyster mushroom. The enzyme possesses a molecular mass of 14 kDa, and is unadsorbed on DEAE-cellulose and adsorbed on Affi-gel blue gel and CM-cellulose. A pH of 7 is required for the enzyme to exhibit maximal activity. The activity of the enzyme does not vary appreciably over the temperature range 30-60 degrees C, but drops when the temperature is reduced to 20 degrees C or raised to and above 70 degrees C. The ribonuclease does not exert any inhibitory activity toward HIV-1 reverse transcriptase. Copyright 2004 Elsevier Inc.