ISSN:
1432-0614
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Process Engineering, Biotechnology, Nutrition Technology
Notes:
Abstract The major serine proteinase of Streptomyces sp. strain C5-A13, a proteinase-overproducing mutant strain, was purified to homogeneity. It has a relative molecular mass (Mr) of 19500 as determined by sodium dodecyl sulphate-polyacrylamide gel electrophoresis and Superose-6 gel filtration chromatography, a low isoelectric point, optimal activity at pH 8.5–9.5, and an optimal temperature of approx. 55°C. This purified enzyme has a high specific activity on azocasein of 11000 units·mg−1 of protein, a K m of 2.7×10−5 m and a Vmax of 2.0 μmol·min−1·mg−1 of protein when succinyl-alanyl-alanyl-prolyl-phenylalanine p-nitroanilide was used as substrate. It was inhibited by the serine proteinase inhibitors diisopropyl fluorophosphate and phenylmethyl-sulfonyl fluoride but not by ethylenediaminetetraacetate (EDTA) or N-tosyl-l-phenylalanine chloromethyl ketone. Thus, this serine proteinase appears to be a chymotrypsin-like enzyme and represents nearly 90% of the total extracellular azocasein-hydrolyzing activity produced by strain C5-A13. Since CaCO3 did not stimulate activity of the purified enzyme itself, the carbonate effect may be a transcriptional or translational rather than a post-translational one.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00166851
Permalink
