A product‐regulated fructose 2,6‐bisphosphatase occurs in green leaves

Publisher Website
Google Scholar
Abstract
An enzyme catalyzing the hydrolytic conversion of fructose 2,6‐bisphosphate (Fru‐2,6‐P2) to fructose 6‐phosphate (Fru‐6‐P) and Pi has been identified and purified from plants, specifically the cytosolic fraction of spinach leaf parenchyma cells. Partially purified preparations of the enzyme, designated fructose 2,6‐bisphosphatase (Fru‐2,6‐P2ase), were inhibited by products of the reaction (i.e., Pi and Fru‐6‐P) but showed no response to a protein phosphorylation system known to inhibit the corresponding enzyme in mammalian cells. Fru‐2,6‐P2ase co‐purified with fructose 6‐phosphate,2‐kinase, the enzyme catalyzing the synthesis of Fru‐2,6‐P2. The observed pattern of regulation of the enzymes functional in the synthesis and breakdown of Fru‐2,6‐P2 reinforces the conclusion that chloroplasts play a role in controlling cytosolic carbon processing in leaves.