Synchronous Cultures of Chlamydomonas reinhardti: Properties and Regulation of Repressible Phosphatases

Abstract

Abstract De novo synthesis of phosphatase (derepression) in orthophosphate deprived synchronously growing Chlamydomonas reinhardti has been demonstrated by using a double labelling isotope technique coupled with cellulose acetate electrophoresis. Repressed and derepressed phosphatase exhibited different enzymatic properties as pH optimum, electrophoretic pattern, Km and Ki values. Especially the acid phosphatase was located near the cell surface.Inorganic, cold TCA‐extractable 32P, decreased during the first 1–2 h after phosphate deprivation when there was little or no net synthesis of phosphatase.Results of experiments with additions of orthophosphate and cycloheximide to derepressed cells, indicated that the derepressible enzyme was relatively unstable, while its m‐RNA was relatively stable.