Purity ~90% (SDS-PAGE). Catalyzes the reversible conversion of 3-phosphohydroxypyruvate to phosphoserine and of 3-hydroxy-2-oxo-4-phosphonooxybutanoate to phosphohydroxythreonine. Source: Recombinant protein corresponding to aa1-370 from mouse Psat1, fused to His-SUMO-Tag at N-terminal, expressed in E. coli. Molecular Weight: ~56.5kD AA