title: Purification and characterization of iso-ribonucleases from a novel thermophilic fungus.
abstract: A thermophilic fungus previously isolated from composted horse manure was found to produce extracellular iso-RNases that were purified 127.6-fold using a combination of size exclusion chromatography and a novel affinity membrane purification system. The extent of purification was determined electrophoretically using 4%-15% gradient polyacrylamide gels. RNase activity was dependent on the presence of a metal co-factor with significantly more activity with Zn2+ or Mn2+ than Mg2+. The RNases exhibited maximum activity at both pH 3.0 and pH 7.0 with no activity at pH 2.0 or 10.0. The optimal temperature for the iso-RNase was 70 °C. The molecular weight of the iso-RNase was determined to be 69 kDa using a Sephadex G-75 column.
authors.affiliation: Department of Food Science, Massachusetts Agricultural Experiment Station, University of Massachusetts, Amherst, MA 01003, USA. kslandry@foodsci.umass.edu.
authors.forename: Kyle S
authors.initials: KS
authors.lastname: Landry
authors.affiliation: Department of Food Science, Massachusetts Agricultural Experiment Station, University of Massachusetts, Amherst, MA 01003, USA. relevin@foodsci.umass.edu.
authors.forename: Robert E
authors.initials: RE
authors.lastname: Levin
mesh_terms: D002413:Cations, Divalent / Q000737:chemistry; D002597:Chaetomium / Q000201:enzymology*; D005656:Fungal Proteins / Q000737:chemistry*; D012260:Ribonucleases / Q000737:chemistry*
chemical_list: D002413:Cations, Divalent; D005656:Fungal Proteins; D012260:Ribonucleases