Purification and partial characterization of spinach leaf glycerate kinase

Glycerate kinase from spinach leaves was purified to near homogeneity using PEG/MgCl2 fractionation, ion exchange, molecular sieving and affinity chromatography. The purified enzyme is a monomer of M r 40 000, shows a pI‐value of 4.8 and a broad pH optimum of 6.5–8.5 and is specific for D‐isomer of glycerate. The high activity of crude enzyme (≈ 150 μmol. h−1.mg chl−1) indicates that glycerate kinase does not limit the oxidative photosynthetic carbon cycle.