title: [Investigations of the influence of pH on the oxidative degradation of glucose by E. coli (biochemical glucose demand) (author's transl)].
abstract: The oxidative degradation of glucose by E. coli was studied in the Warburg manometer. The pH of the medium was established in these studies at values between 5.5 and 8.0. Analysis of the reaction kinetics by plotting time/consumption curves shows that three consecutive reactions can be distinguished as the substrate is eliminated from the medium: An adaptation phase which is generally relatively brief is followed by two reactions, of which the first proceeds more rapidly or more slowly than reaction 3, depending on pH. The important feature in reactions 1 and 2 is that the oxygen demand is evidently independent of the initial concentration of substrate. In spite of these differences, if the reaction is regarded as a whole, there are no relations involving significant dependence on pH of medium. Neither the substrate-specific biochemical oxygen demand nor the reaction time necessary for catabolism show statistically significant dependence within the range of pH examined. It can be assumed therefore that E. coli possesses a regulation mechanism which compensates for unfavourable environmental conditions. The division of substrate catabolism into constituent reactions, combined with a change in concentration of pacemaker enzyme and a "competitive inhibition" may be of significance in this regulations.
mesh_terms: D004926:Escherichia coli / Q000378:metabolism*; D005947:Glucose / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008365:Manometry; D010084:Oxidation-Reduction; D010101:Oxygen Consumption
chemical_list: D005947:Glucose
vernacular_title: Untersuchungen über den Einfluss des pH-Wertes auf den oxydativen Abbau (BSB) von Glucose durch E. coli