In steady-state kinetic studies of ox liver glutamate dehydrogenase in 0.11 M-potassium phosphate buffer, pH7, at 25 degrees C, the concentration of ADP was varied from 0.5 to 1000 microM. Inhibition was observed except when the concentrations of both glutamate and coenzyme were high, when activation was seen. With NAD+ or NADP+ as coenzyme, 200 microM-ADP was sufficient to saturate the enzyme with respect to the major effect of this nucleotide. In the presence of 210 microM-ADP, widely varied concentrations of coenzyme give linear Lineweaver-Burk plots, in marked contrast with results obtained previously for kinetics without ADP. This has allowed evaluation for the reaction with NAD+, NADP+ and acetylpyridine-adenine dinucleotide (315 microM-ADP in the last case) of all four initial rate parameters, i.e. the phi coefficients in the equation: (Formula: see text) where A is coenzyme and B is glutamate. The relative constancy of phi B and of phi AB/phi A with the different coenzymes point to a compulsory-order mechanism with glutamate as the leading substrate. This conclusion, though unexpected, agrees well with various previous observations on the binding of oxidized coenzyme.
Skip Nav Destination
Article navigation
October 1984
-
Cover Image
Cover Image
- PDF Icon PDF LinkFront Matter
- PDF Icon PDF LinkTable of Contents
- PDF Icon PDF LinkAdvertising
Research Article|
October 01 1984
The kinetic mechanism of ox liver glutamate dehydrogenase in the presence of the allosteric effector ADP. The oxidative deamination of L-glutamate
Publisher: Portland Press Ltd
Online ISSN: 1470-8728
Print ISSN: 0264-6021
© 1984 London: The Biochemical Society
1984
Biochem J (1984) 223 (1): 161–168.
Citation
D P Hornby, M J Aitchison, P C Engel; The kinetic mechanism of ox liver glutamate dehydrogenase in the presence of the allosteric effector ADP. The oxidative deamination of L-glutamate. Biochem J 1 October 1984; 223 (1): 161–168. doi: https://doi.org/10.1042/bj2230161
Download citation file:
Sign in
Don't already have an account? Register
Sign in to your personal account
You could not be signed in. Please check your email address / username and password and try again.
Could not validate captcha. Please try again.