Open AccessRelease of Glucose from Purified Galactose‐Binding Protein of Escherichia coli upon Addition of Galactose
Author(s) -
Richarme Gilbert,
Kepes Adam
Publication year - 1974
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1974.tb03537.x
Subject(s) - galactose , chemistry , biochemistry , escherichia coli , kinetics , chromatography , dissociation (chemistry) , stereochemistry , organic chemistry , quantum mechanics , gene , physics
The galactose‐binding protein which forms an essential component of the galactose transport system, called β‐methyl galactose permease, shows a galactose binding behavior that cannot be described by the usual association‐dissociation equilibrium equations. It was found that the amount of [ 14 C]galactose bound was dependent on the ratio of the amounts of galactose to galactose‐binding protein present in the reaction mixture. It is shown furthermore, that addition of galactose to its binding protein results in the release of another ligand, which by an enzymatic assay and by thin‐layer chromatography was shown to be glucose. The glucose liberated upon addition of [ 14 C]galactose was non‐radioactive, and approximately equivalent to the [ 14 C]galactose bound. An exchange equilibrium between glucose and galactose can account for the distorted “binding” kinetics.