Highly purified branched-chain 2-oxo acid dehydrogenase complex (BCOADC) oxidizes 4-methylthio-2-oxobutyrate and 2-oxobutyrate, with Km values of 67 microM and 18 microM respectively. The Vmax. for oxidation of these substrates is 27% and 53% respectively of that for 3-methyl-2-oxobutyrate. Highly purified pyruvate dehydrogenase complex (PDC) oxidizes 2-oxobutyrate (Km 100 microM; Vmax. 49% of that for pyruvate) but not 4-methylthio-2-oxobutyrate, whereas 2-oxoglutarate dehydrogenase complex will not utilize either 2-oxo acid as substrate. BCOADC kinase is inhibited by both 4-methylthio-2-oxobutyrate and 2-oxobutyrate, with half-maximal inhibition by 45 microM and 50 microM respectively. Phosphorylation of BCOADC in isolated adipocytes is inhibited by both 4-methylthio-2-oxobutyrate and 2-oxobutyrate, consistent with their inhibitory action of BCOADC kinase. Phosphorylation of PDC is decreased by 2-oxobutyrate, but not by 4-methylthio-2-oxobutyrate.
Skip Nav Destination
Article navigation
July 1986
-
Cover Image
Cover Image
- PDF Icon PDF LinkFront Matter
- PDF Icon PDF LinkTable of Contents
- PDF Icon PDF LinkAdvertising
Research Article|
July 15 1986
Oxidative decarboxylation of 4-methylthio-2-oxobutyrate by branched-chain 2-oxo acid dehydrogenase complex
Publisher: Portland Press Ltd
Online ISSN: 1470-8728
Print ISSN: 0264-6021
© 1986 London: The Biochemical Society
1986
Biochem J (1986) 237 (2): 621–623.
Citation
S M A Jones, S J Yeaman; Oxidative decarboxylation of 4-methylthio-2-oxobutyrate by branched-chain 2-oxo acid dehydrogenase complex. Biochem J 15 July 1986; 237 (2): 621–623. doi: https://doi.org/10.1042/bj2370621
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.