Polyphosphate kinase of Acinetobacter sp. strain ADP1: purification and characterization of the enzyme and its role during changes in extracellular phosphate levels.

ABSTRACT: Polyphosphate (polyP) is a ubiquitous biopolymer whose function and metabolism are incompletely understood. The polyphosphate kinase (PPK) of Acinetobacter sp. strain ADP1, an organism that accumulates large amounts of polyP, was purified to homogeneity and characterized. This enzyme, which adds the terminal phosphate from ATP to a growing chain of polyP, is a 79-kDa monomer. PPK is sensitive to magnesium concentrations, and optimum activity occurs in the presence of 3 mM MgCl(2). The optimum pH was between pH 7 and 8, and significant reductions in activity occurred at lower pH values. The greatest activity occurred at 40 degrees C. The half-saturation ATP concentration for PPK was 1 mM, and the maximum PPK activity was 28 nmol of polyP monomers per microg of protein per min. PPK was the p

SUBMITTER: Trelstad PL 

PROVIDER: S-EPMC99700 | biostudies-literature | 1999 Sep

REPOSITORIES: biostudies-literature