Isolation, cloning, and gene expression analysis of phosphoglycolate phosphatase from green alga .

Phosphoglycolate phosphatase (PGPase), a key enzyme in photosynthetic organisms, catalyzes the dephosphorylation of phosphoglycolate, which is largely produced by the oxygenase activity of Rubisco, and is a potent inhibitor of several Calvin cycle enzymes. PGPase (CrPGPase 1) was previously cloned, purified, and characterized from unicellular green . analysis revealed two more candidates encoding PGPase enzymes in the genome. In this study, we isolated, cloned, and overexpressed three PGPase genes (, , ) from and performed gene expression analysis at high and low ammonium [NH ] concentrations. We demonstrate that all three genes encode functionally active PGPases in . In addition, we show that and genes are N-responsive genes and are upregulated under low ammonium concentrations. analysis revealed that PGPase exists mainly in three isoforms in higher plants and algae.