Kinetic studies of the mechanism of sheep liver cytoplasmic aldehyde dehydrogenase.
Initial-rate studies of aldehyde oxidation have been conducted with propionaldehyde and butyraldehyde over a wide range of substrate concentrations and covering the region where activation by high substrate concentration occurs. The studies at low aldehyde concentrations are consistent with a compulsory mechanism with NAD+ binding first. Stopped-flow studies using spectrophotometric and fluorimetric methods shows a more complex picture, however. The major transients in fluorescence are much slower than those seen by absorbance and pre-mixing enzyme with NAD+ appears to alter the course of the pre-steady state phase of the reaction. The enzyme is activated by fairly high concentrations (0.1-0.5 M) of ethanol, propanol, propan-2-ol etc. and is markedly inhibited by very low concentrations of bivalent metal ions. The basis of these effects is discussed.
D000444:Aldehyde Dehydrogenase; D000445:Aldehyde Oxidoreductases / Q000378:metabolism*; D000818:Animals; D007700:Kinetics; D008099:Liver / Q000201:enzymology*; D009243:NAD; D012756:Sheep; D013379:Substrate Specificity
D009243:NAD; D000445:Aldehyde Oxidoreductases; D000444:Aldehyde Dehydrogenase