L-pipecolic acid metabolism in human liver: L-alpha-aminoadipate delta-semialdehyde oxidoreductase.
A soluble enzyme that catalyzes the oxidation of L-alpha-aminoadipate delta-semialdehyde to L-alpha-aminoadipic acid in the presence of NAD+ has been isolated and characterized from human liver. This enzyme L-alpha-aminoadipic delta-semialdehyde oxidoreductase has been found to be localized in the cytosol using subcellular fractionation and marker enzyme assays. The reaction product of this enzyme has been identified as L-alpha-aminoadipic acid by use of an amino acid analyzer and thin layer chromatography. The enzymatic reaction was irreversible and has a pH optimum of 8. The enzyme was stimulated by Mg2+, Cu2+ and Mn2+, and has a requirement of free -SH groups. The Km and Vmax values for its substrate L-alpha-aminoadipate delta-semialdehyde were shown to be 181 microM and 71.4 pmol.min-1.mg-1, respectively, and for its coenzyme NAD+ to be 454 microM and 142.9 pmol.min-1.mg-1, respectively. The characteristics of the oxidoreductase obtained from the human liver and Pseudomonas putida were compared.
Chang
Y F
YF
Department of Biochemistry, University of Maryland, Dental School, Baltimore 21201.
Ghosh
P
P
Rao
V V
VV
D015074:2-Aminoadipic Acid / Q000031:analogs & derivatives / Q000378:metabolism; D000328:Adult; D000445:Aldehyde Oxidoreductases / Q000378:metabolism*; D003067:Coenzymes / Q000378:metabolism; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D050647:L-Aminoadipate-Semialdehyde Dehydrogenase; D008099:Liver / Q000201:enzymology / Q000378:metabolism*; D008830:Microbodies / Q000201:enzymology / Q000378:metabolism*; D010875:Pipecolic Acids / Q000378:metabolism*; D011205:Povidone; D011549:Pseudomonas / Q000201:enzymology / Q000378:metabolism; D012822:Silicon Dioxide; D013379:Substrate Specificity
D003067:Coenzymes; D010875:Pipecolic Acids; D015074:2-Aminoadipic Acid; C000061:allysine; C016039:Percoll; D012822:Silicon Dioxide; D000445:Aldehyde Oxidoreductases; D050647:L-Aminoadipate-Semialdehyde Dehydrogenase; D011205:Povidone; C031345:pipecolic acid