Kinetic studies of the old yellow enzyme. I. The reaction mechanism of the enzyme with reduced nicotinamide adenine dinucleotide.
Biochimica et biophysica acta
confidence
Key findings
Kinetic study of old yellow enzyme with NADH; no involvement of free radical of flavin semiquinone in reaction process.
View source on PubMed (PMID 196654) ↗
- Sample size
- N/A
- Population
- In vitro enzyme kinetics study
- Dosing
- NADH as substrate
- Duration
- N/A
- Route
- in vitro
- Blinding
- not_reported
- Controls
- none
- Drug class
- coenzyme
Full abstract
The reaction mechanism of old yellow enzyme (NADPH:(acceptor) oxidoreductase, EC 1.6.99.1) was kinetically investigated using NADH as substrate. The enzyme was reduced by NADH via a reaction intermediate which has a specific absorption spectrum. This intermediate decomposed to yield a reduced enzyme and NAD+ through an inrreversible first-order reaction step. The reduced enzyme was reoxidized by oxygen through a second-order reaction process. Individual values of elementary rate constants were measured and a computer simulation of the reaction process was carried out. No involvement of free radical of flavin semiquinone in the reaction process could be shown.