Purification and characterization of a new ribonuclease from fruiting bodies of the oyster mushroom Pleurotus ostreatus.
A ribonuclease (RNase), possessing an N-terminal sequence disparate from those of ribonucleases from other mushrooms and previously isolated Pleuotus ostreatus RNases, was purified from the fruiting bodies of the edible mushroom Pleurotus ostreatus. The N-terminal sequence of Pleurotus ostreatus RNase did not manifest homology even to a previously reported RNase from the same mushroom. The ribonuclease was adsorbed on CM-Sepharose and Mono S. It exhibited a molecular mass of 12 kDa in both sodium dodecyl sulphate-polyacrylamide gel electrophoresis and gel filtration on Superdex 75. The ribonuclease displayed an activity of 11490 U/mg on yeast tRNA. The highest ribonuclease activity was exhibited toward poly U, followed by poly A and poly C. No activity was shown toward poly G. The optimal pH for its activity was 7 and the optimal temperature was 55 degrees C. It inhibited cell-free translation in a rabbit reticulocyte lysate with an IC50 of 240 nM.
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Department of Biochemistry, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China.
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D000595:Amino Acid Sequence; D004591:Electrophoresis, Polyacrylamide Gel; D005638:Fruit / Q000201:enzymology*; D008969:Molecular Sequence Data; D020076:Pleurotus / Q000201:enzymology* / Q000254:growth & development; D012260:Ribonucleases / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism*
D012260:Ribonucleases