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Inorganic pyrophosphate:D-fructose-6-phosphate 1-phosphotransferase in mung beans and its activation by D-fructose 1,6-bisphosphate and D-glucose 1,6-bisphosphate

1981; Elsevier BV; Volume: 100; Issue: 4 Linguagem: Inglês

10.1016/0006-291x(81)90677-x

1090-2104

Dario C. Sabularse, Richard L. Anderson,

Enzyme Structure and Function

Inorganic pyrophosphate: D-fructose-6-phosphate 1-phosphotransferase was detected in extracts of mung bean sprouts, the first such detection in C3 plants. The enzyme had an absolute requirement for a divalent metal (Mg++) as well as for D-fructose 6-phosphate and inorganic pyrophosphate. An examination of anomalous kinetics revealed that the enzyme was activated by a product of the reaction, D-fructose 1,6-bisphosphate; micromolar concentrations of this effector increased the activity of the enzyme about 20-fold. D-Glucose 1,6-bisphosphate at higher concentrations could substitute for D-fructose 1,6-bisphosphate as an activator, but not as a substrate in the reverse reaction. The enzyme was fully active under conditions wherein ATP: D-fructose-6-phosphate 1-phosphotransferase from the same source was inhibited >99% (e.g., in the presence of 10 μM phosphoenolpyruvate).