PHOSPHATASES OF MARINE ALGAE

Abstract

1. Phosphate-repressible alkaline phosphatases were found in axenic cultures of marine algae, especially Chrysophyceae and Bacillariophyceae. Enzyme synthesis started when the algae became phosphorus-deficient and stoped if phosphate was restored to the medium.2. Maximal enzyme activity was usually above pH 9, but significant activity was also present at ordinary sea water pH, approximately pH 8.3. The phosphatases enabled algae to split glucose-6-phosphate; the phosphate was quickly assimilated but the glucose moiety remained in the medium. Algae took phosphorus from adenosine monophosphate and α-glycerophosphate at the same rate as from glucose-6-phosphate.4. The phosphatases appear to be firmly bound near the cell surface. They may enable deficient algae to regenerate phosphate from soluble organic phosphorus compounds present in natural sea water.