title: Isolation of high-Km aldehyde dehydrogenase isoenzymes from human gastric mucosa.
abstract: Human stomach aldehyde dehydrogenase-3 isoenzymes were isolated by DEAE-cellulose, CM-Sephadex, and 5' AMP-Sepharose chromatographies to apparent homogeneity. The subunit of the isoenzymes was determined to be 55,000 daltons by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The kinetic constants for oxidation of various aliphatic and aromatic aldehydes were determined. The Km value for straight-chain aldehydes decreased over 9,000 fold when chain length increased from C2 to C7. The Vmax/Km value for heptaldehyde was 10-fold higher than that for benzaldehyde. NAD+ was a much better cosubstrate than NADP+. The human stomach aldehyde dehydrogenase-3 isoenzymes were insensitive to disulfiram inhibition and were not activated or inhibited by magnesium ions.
authors.affiliation: Department of Biochemistry, National Defense Medical Center, Taipei, Taiwan, Republic of China.
authors.forename: S L
authors.initials: SL
authors.lastname: Wang
authors.forename: C W
authors.initials: CW
authors.lastname: Wu
authors.forename: T C
authors.initials: TC
authors.lastname: Cheng
authors.forename: S J
authors.initials: SJ
authors.lastname: Yin
mesh_terms: D000444:Aldehyde Dehydrogenase / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism; D000447:Aldehydes / Q000378:metabolism; D002845:Chromatography; D004591:Electrophoresis, Polyacrylamide Gel; D005753:Gastric Mucosa / Q000201:enzymology*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007527:Isoenzymes / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism; D007700:Kinetics; D008099:Liver / Q000201:enzymology; D008970:Molecular Weight; D009243:NAD / Q000378:metabolism; D009249:NADP / Q000378:metabolism; D010084:Oxidation-Reduction; D013379:Substrate Specificity
chemical_list: D000447:Aldehydes; D007527:Isoenzymes; D009243:NAD; D009249:NADP; D000444:Aldehyde Dehydrogenase