Abstract
Abstract Horse liver aldehyde: NAD oxidoreductase (EC 1.2.1.3) has been purified to homogeneity by a procedure consisting of salt fractionation, ion exchange chromatography, and isoelectric focusing. The purified material has a turnover number of 1.85 µmoles of NADH per min per mg of protein when assayed at pH 9.0 with propionaldehyde as substrate. Values obtained for the molecular weight of the native enzyme by sucrose density centrifugation, sedimentation equilibrium, and multiple porosity disc gel electrophoresis were 220,000, 260,000, and 252,000, respectively. Sodium dodecyl sulfate polyacrylamide gel electrophoresis indicated a subunit molecular weight of 57,000, suggesting a tetrameric structure for the native enzyme. Specificity studies indicated that both aromatic and aliphatic aldehydes were oxidized. For most aldehydes tested, the Michaelis constants were between 0.1 to 1 µm when corrected for equilibrium concentrations of inactive hydrated aldehyde. Chloral, which is completely hydrated, was an inhibitor of the dehydrogenase reaction. Despite the broad aldehyde specificity, substrate analogues in which the aldehydic hydrogen of RCHO was replaced by NH2, CH3, or even OH were not found to be inhibitors.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
