Substrate specificity of the phosphorylated fructose-1,6-bisphosphatase dephosphorylating protein phosphatase from Saccharomyces cerevisiae |
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Authors: | A Manhart H Holzer |
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Affiliation: | Biochemisches Institut, Universit?t Freiburg, West Germany. |
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Abstract: | Enzymatic dephosphorylation of the phosphorylated forms of five different yeast enzymes has been studied: fructose-1,6-bisphosphatase, glycogen phosphorylase, neutral trehalase, NAD-glutamate dehydrogenase and 6-phosphofructo-2-kinase. Phosphorylated fructose-1,6-bisphosphatase and phosphorylated 6-phosphofructo-2-kinase were present in extracts of starved yeast cells which had been incubated for 10 min with glucose. Phosphorylated glycogen phosphorylase, neutral trehalase and NAD-glutamate dehydrogenase were obtained by incubation of yeast extract with ATP, cyclic AMP and Mg2+. After incubation with commercially available preparations of alkaline phosphatase, all five phosphorylated enzymes studied showed the changes in catalytic activity that would be expected as a consequence of dephosphorylation. The recently purified yeast enzyme which dephosphorylates phosphorylated fructose-1,6-bisophosphatase (Horn and Holzer (1987) however, was found to be active only with the phosphorylated fructose-1,6-bisphosphatase, but not with the other four phosphorylated enzymes studied. By contrast, a crude extract from yeast showed dephosphorylating activity towards all five substrates. Substrate specificity with the five phosphorylated enzymes studied of different phosphoprotein phosphatases from yeast prepared by others is discussed. |
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Keywords: | Furctose-1 6-biophosphatase Saccharomyces cerevisiae specificity of phosphatases |
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