Extracellular acid phosphatase as a minor enzyme during the production of proteinases by Humicola lutea 120–5 |
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Authors: | B Tchorbanov P Aleksieva N Dambadarja G Dyulgerova |
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Abstract: | Extracellular acid phosphatase was studied as a minor enzyme of the fungal strain Humicola lutea 120–5 having a clear relation to the secretion of acid proteinases. A medium lacking in mineral orthophosphates ensured a fivefold higher yield of phosphatase while the proteinase production was reduced. An acid phosphatase fraction free of proteinase activity was isolated demonstrating a maximum hydrolysis of 4-nitrophenyl-phosphate at a pH of 4.0 and 50°C. The phosphatase catalyzed a partial dephosphorylation of up to 30% of casein at a pH of 3.0 causing a complete substrate precipitation. Both proteinase and phosphatase biosynthesis increased twofold when natural casein was replaced by partially dephosphorylated casein in the cultivation medium. |
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