MULTIPLE FORMS OF ADP-GLUCOSE PYROPHOSPHORYLASE FROM TOMATO LEAF

ADP-glucose pyrophosphorylase (AGP, EC 2.7.7.27) was partially purifie d from tomato (Lycopeisicon esculentum Mill. cv. Laura) leaf by a proc edure previously used for purification of AGP from tomato pericarp. SD S-PAGE and western blot analysis of the final preparation indicated th at the leaf enzyme is composed of two subunits of 50 and 54 kDa. Two-d imensional PAGE and western blot analysis of the same preparation, how ever, revealed at least six isoforms of the large subunit and two isof orms of the small subunit. The leaf AGP is very sensitive to regulatio n by 3-phosphoglycerate and inorganic phosphate. Its properties are co mpared to those of AGP from tomato fruit.