A mutation altering some properties of the neutral phosphatase in Chlamydomonas reinhardi: possible post-translational modification of phosphatase structure

A mutant (PDs-) of Chlamydomonas reinhardi has been isolated which produces an altered neutral phosphatase. The wild-type (PDs+) and mutant (PDs-) phosphatases markedly differed in their thermosensitivities and electrophoretic mobilities. The heterozygous PDs-/PDs+ diploids produced only the wild-type electrophoretic form of the phosphatase. Mixing extracts of PDs- with extracts of various other strains in vitro resulted in the rapid transformation of the PDs- enzymic form into an enzymic variety, the properties (heat sensitivity, electrophoretic mobility) of which were similar to those of the wild-type neutral phosphatase. The results are discussed in relation to the idea that the PDs mutation is located not in the structural gene but rather in a modifying gene acting at the post-translational level.