Premium
Characterization of yeast fructose‐2,6‐bisphosphate 6‐phosphatase
Author(s) -
Plankert Uwe,
Purwin Claudio,
Holzer Helmut
Publication year - 1988
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(88)80547-7
Subject(s) - fructose 2,6 bisphosphate , fructose , michaelis–menten kinetics , fructolysis , phosphatase , steady state (chemistry) , chemistry , biochemistry , fructose 1,6 bisphosphatase , enzyme , enzyme assay , glycolysis , phosphofructokinase
To obtain information on the biological significance of yeast fructose‐2,6‐bisphosphate 6‐phosphatase, kinetic data of the purified enzyme [(1987) Eur. J. Biochem. 164, 27–30] have been measured. Maximal activity was found between Ph 6 and 7, the apparent Michaelis constant with fructose 2,6‐bisphosphate was 7.2 μM at Ph 6.0 and 79 μm at Ph 7.0. Concentrations required for 50% inhibition of the enzyme at Ph 6.0 were 8 μm Fru2P, 45 μm G1c6P, 80 μm Fru6P and 200 μm inorganic phosphate. The known intracellular steady‐state level of about 10 μm fructose 2,6‐bisphosphate in the presence of glucose is likely to be the result of a balance between the rapid synthesis of fructose 2,6‐bisphosphate catalyzed by 6‐phosphofructose 2‐kinase and a fructose 2,6‐bisphosphate degrading activity. The biological function of fructose‐2,6‐bisphosphate 6‐phosphatase with an apparent Michaelis constant between 7 and 79 μm fructose 2,6‐bisphosphate at Ph 6–7 is therefore suggested to participate in the maintenance of a steady‐state level of fructose 2,6‐bisphosphate in a concentration range that fits well with the Michaelis constant of the enzyme.