Purification and Partial Characterization of Inactive Pyruvate Orthophosphate Dikinase from Dark-treated Maize Leaves

Abstract

To elucidate the mechanism of light-activation of pyruvate P₁ dikinase in maize leaf, the nactive form was purified to homogeneity from dark-treated leaves using an activation system to locate it. The purification procedure included ammonium sulfate-fractionation followed by conventional chromatography.
The homogeneous enzyme after maximal activation had a specific activity comparable to that of the active enzyme obtained from non-dark-treated plants. The enzyme was indistinguishable from the active one in its molecular size and charge and in the amino acid composition of its acid-hydrolysate.