Some Properties of Alkaline Phosphatase of <i>Pseudomonas fluorescens</i>

Abstract

The formation of alkaline phosphatase in a strain of Pseudomonas fluorescens was found to be induced by limiting quantities of orthophosphate in the extracellular medium. The substrate specificity of this enzyme seemed to be similar to that of Escherichia coli . On the other hand, it had some properties different from those of the E. coli enzyme. The Pseudomonas enzyme was several hundred fold more sensitive to inhibition by EDTA, but was not inhibited by cyanide and by various mercaptans. The apparent K m for p ‐nitrophenylphosphate was 2.0x10 −4 M and K i for orthophosphate as a competitive inhibitor was 3.7 × 10 −5 at pH 8.6.