Fructose-6-phosphate 2-kinase and fructose 2,6-bisphosphatase have been partially purified from maize leaves by PEG fractionadon and by chromatography on TSK-DEAE ion exchanger and Blue-Sepharose 4B. Fructose-6-phosphate 2-kinase was activated by phosphate and inhibited by 3-pnosphoglycerate. Furctose 2,6-bisphosphatase was inhibited by inorganic phosphate and fructose-6-phosphate.The observed pattern of reguladon suggests that systhesis and degradation of Fru-2,6-P2 respond to changes in the concentration of effectors. An increase in the level of glycerate-3-phosphate or dihydroxyacetonephosphate will result in a decrease in the level of Fru-2,6-P2. Conversely a rise in Fru-6-P concentration will lead to an increase in the Fru-2, 6-P2 concentration.