Muscle fructose-1,6-diphosphatase

Although gluconeogenesis is generally considered to be confined to liver and kidney, evidence for the presence of a specific FDPase in muscle has been reported from a number of laboratories. Significant levels of activity are to be found in skeletal muscle of a wide variety of vertebrates including mammals, birds, and amphibia (71, 72). The levels of activity in white muscle were reported to be similar to those found in liver and kidney, but the enzyme was not detected in heart muscle or in smooth muscle of several species tested. Fructose diphosphatase in crude muscle extracts has been reported to be stimulated by EDTA (72). 

Clark, M. G., Bloxham, D.P., Holland, P. C., and Lardy, H. A., 1973, Estimation of the fructose diphosphatase-phosphofructokinase substrate cycle in the flight muscle of Bombus affinis, Biochem. J. 134 589. 

Fructose 1,6-diphosphatase can be isolated from many mammalian systems, including rabbit liver,360 muscle,361,362 rabbit kidney,363 swine... 

D-Fructose 1,6-diphosphatases from rabbit liver and muscle are similar in their cation-requirement profile, molecular weight, substrate affinity, and substrate inhibition, but have different amino acid compositions, and the muscle enzyme does not cross-react with antibody to the purified liver-enzyme.361,364 The muscle enzyme is more sensitive to AMP than the enzyme from liver or kidney.385... 

Taketa and coworkers398 reported that ATP and ADP inhibit rabbit-liver D-fructose 1,6-diphosphatase, and that the inhibition results from a conversion of the enzyme into a conformer having low activity. Skeletal-muscle enzyme is inhibited by ADP. 

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