Patel TR, Jackman DM, Bartlett FM. Heat-stable protease from Pseudomonas fluorescens T16: purification by affinity column chromatography and characterization.
Appl Environ Microbiol 1983;
46:333-7. [PMID:
6414369 PMCID:
PMC239382 DOI:
10.1128/aem.46.2.333-337.1983]
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Abstract
A heat-stable extracellular protease from Pseudomonas fluorescens T16, a psychrotroph, was purified by affinity column chromatography on a carbobenzoxy-D-phenylalanine-triethylene tetramine-Sepharose-4B column. The purified enzyme is a monomer with a molecular weight of 38,905 +/- 2,000. In an analytical ultracentrifuge, the Schlieren profile revealed a single symmetrical peak. The sedimentation coefficient was estimated to be 3.93S. Alpha-casein was the preferred substrate, with a Km of 0.05 mM. Heating crude enzyme and purified enzyme in buffer at 50, 90, and 120 degrees C resulted in a rapid initial loss of more than 50% of the initial activity followed by a gradual inactivation which exhibited first-order kinetics. The activation energy for the hydrolysis of casein was calculated to be 3.2 kcal/mol (13.4 kJ/mol).
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