Purification and Properties of Intracellular Proteinase from Streptococcus cremoris
Open Access
- 1 January 1975
- journal article
- research article
- Published by American Society for Microbiology in Applied Microbiology
- Vol. 30 (5) , 738-745
- https://doi.org/10.1128/aem.30.5.738-745.1975
Abstract
Proteolytic activity in the extract from the cells of Streptococcus cremoris increased in the presence of casein, lactose, glucose, and CaCl2 in the media but was negligibly detectable in the extract of the cells harvested from the culture containing succinate or citrate. The intracellular proteinase from S. cremoris harvested from tomato medium was purified 150-fold in this experiment. The enzyme had a molecular weight of 140,000, optimum pH at 6.5 to 7.0, and maximum activity at 30 C. The proteinase was activated by Ca2+ and inhibited by Zn2+, Cu2+, Hg2+, Fe2+, ethylenediaminetetraacetate, and sodium lauryl sulfate. The Km value of the enzyme towards each casein fraction was almost the same, and the Vmax of the enzyme towards αs-casein was smaller than those towards the other casein fractions. ImagesKeywords
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