In Vitro Phosphorylation of Phosphoenolpyruvate Carboxylase from the Green Alga Selenastrum minutum

摘要: ;Previously, we described two distinct classes of phosphoenolpyruvate carboxylase (PEPC) isoforms in the green alga Selenastrum minutum. Class 1 PEPC (PEPC1) is a homotetramer composed 102 kDa subunits (p102), whereas 2 PEPCs exist as three large protein complexes (PEPC2–PEPC4) containing varying proportions structurally dissimilar p102 and 130 (p130) catalytic subunits. In current study, calciumindependent kinase was shown to co-purify with PEPC1, but not PEPC2. However, p130 subunit PEPC2 phosphorylated vitro during its incubation presence [- 32 P]ATP clarified algal extract. Treatment purified phosphatase 2A2 increased apparent Mr judged by Superose 6 gel filtration chromatography. The inhibitors NaF microcystin-LR throughout purification significantly influenced activity structural organization 2, 1, isoforms. results are consistent notion that under culture conditions employed: (i) vivo mainly their dephosphorylated forms, respectively, (ii) phosphorylation leads significant reduction native M r . We propose kinase-mediated involved control PEPC.