May 25, 1976

Purification and characterization of a repressible alkaline phosphatase from Thermus aquaticus

The Journal of Biological Chemistry
M F Yeh, J M Trela


A repressible alkaline phosphatase has been isolated from the extreme bacterial thermophile, Thermus aquaticus. The enzyme can be derepressed more than 1,000-fold by starving the cells for phosphate. In derepressed cells, nearly 6% of the total protein in a cell-free enzyme preparation is alkaline phosphatase. The enzyme was purified to homogeneity as judged by disc acrylamide electrophoresis and sodium dodecyl sulfate electrophoresis. By sucrose gradient centrifugation it was established that the enzyme has an approximate molecular weight of 143,000 and consists of three subunits, each with a molecular weight of 51,000. Tris buffer stimulates the activity of the enzyme, which has a pH optimum of 9.2. The enzyme has a broad temperature range with an optimum of 75-80 degrees. The enzyme catalyzes the hydrolysis of a wide variety of phosphorylated compounds as do many of the mesophilic alkaline phosphatases. The Michaelis constant(Km) for the enzyme is 8.0 X 10(-4) M. Amino acid analysis of the protein revealed little in the amino acid composition to separate it from other mesophilic enzymes which have been previously studied.

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Mentioned in this Paper

Enzymes, antithrombotic
Alkaline Phosphatase Measurement
Phosphate Measurement
Alkaline Phosphatase
Enzyme agent
Enzymes for Treatment of Wounds and Ulcers
Purification Aspects

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