title: Purification and characterization of the extracellular proteinase of Pseudomonas fluorescens NCDO 2085.
abstract: Pseudomonas fluorescens NCDO 2085 produced a single heat-stable extracellular proteinase in Na caseinate medium at 20 degrees C and pH 7.0. The proteinase was purified to electrophoretic homogeneity using chromatofocusing, gel filtration and ion-exchange chromatography. The purification procedure resulted in a 158-fold increase in the specific activity and a yield of 3.5% of the original activity. The enzyme is a metalloproteinase containing Zn and Ca, with an isoelectric point at 5.40 +/- 0.05 and a mol. wt of 40 200 +/- 2100. It is heat-stable having D-values at 74 and 140 degrees C of 1.6 and 1.0 min respectively; 40 and 70% of the original activity remained after HTST (74 degrees C/17 s) and ultra high temperature (140 degrees C/4 s) treatments respectively. The amino acid composition of the proteinase was determined and compared with those from other Pseudomonas spp.
mesh_terms: D000596:Amino Acids / Q000032:analysis; D002850:Chromatography, Gel; D004591:Electrophoresis, Polyacrylamide Gel; D010450:Endopeptidases / Q000032:analysis* / Q000302:isolation & purification; D007526:Isoelectric Point; D011551:Pseudomonas fluorescens / Q000201:enzymology*
chemical_list: D000596:Amino Acids; D010450:Endopeptidases