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RESEARCH PRODUCT
Purification and characterization of an exopolyphosphatase from Saccharomyces cerevisiae.
W. E. G. MüllerBernd LorenzI. S. KulaevHeinz-christoph Schrödersubject
chemistry.chemical_classificationbiologyMolecular massChemistryPolyphosphateSaccharomyces cerevisiaeCell Biologybiology.organism_classificationBiochemistryPyrophosphateDivalentchemistry.chemical_compoundEnzymeAffinity chromatographyBiochemistryMolecular BiologyExopolyphosphatasedescription
An exopolyphosphatase (polyphosphate phosphohydrolase; EC 3.6.1.11) activity that cleaves inorganic polyphosphates to orthophosphate has been purified to apparent homogeneity (> 95% pure) from Saccharomyces cerevisiae. The exopolyphosphatase is a monomeric protein with a polypeptide molecular mass of 28 kDa. The enzyme, which can be stabilized in the presence of Triton X-100, has a pH optimum of 7.5 and requires, for maximal activity, Co2+ or Mg2+ ions. In the absence of these ions, the exopolyphosphatase binds to polyphosphate but does not degrade it, allowing affinity purification of the enzyme on a polyphosphate-modified zirconia support. o-Vanadate, Cu2+, and Ca2+ are effective inhibitors of the exopolyphosphatase. The enzyme preferentially hydrolyzes linear polyphosphates in a non-processive manner; pyrophosphate as well as cyclic tri- and tetrametaphosphate are degraded only at very low rates, whereas ATP is not split by the exopolyphosphatase. The only product formed by the action of the enzyme is orthophosphate.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 1994-09-01 | Journal of Biological Chemistry |