Isomerase activity of the C-terminal fructose-6-phosphate binding domain of glucosamine-6-phosphate synthase from Escherichia coli.
The isomerase activity of the C-terminal fructose-6P binding domain (residues 241-608) of glucosamine-6-phosphate synthase from Escherichia coli has been studied. The equilibrium constant of the C-terminal domain k(eq) ([glucose-6P]/[fructose-6-P]) = 5.0. A non-competitive product inhibition of the isomerase activity by the reaction product glucose-6-P has been detected. The existence of more than one binding and reaction sites for the substrate fructose-6P on the molecule of glucosamine-6-phosphate synthase can be expected. The fructose-6P binding domain possibly includes a regulatory site, different from the catalytic center of the enzyme.
Todorova
R
R
Institute of Biophysics, Bulgarian Academy of Sciences, Sofia. todorova@obzor.bio.21.bas.bg
D000595:Amino Acid Sequence; D001665:Binding Sites; D004926:Escherichia coli / Q000201:enzymology*; D005636:Fructosephosphates; D019298:Glucose-6-Phosphate / Q000494:pharmacology; D005945:Glutamine-Fructose-6-Phosphate Transaminase (Isomerizing) / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000378:metabolism; D007535:Isomerases / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000378:metabolism*; D007536:Isomerism; D007700:Kinetics; D017434:Protein Structure, Tertiary
D005636:Fructosephosphates; D019298:Glucose-6-Phosphate; C027618:fructose-6-phosphate; D005945:Glutamine-Fructose-6-Phosphate Transaminase (Isomerizing); D007535:Isomerases