Characterization of an oligomeric carbonyl reductase of dog liver: its identity with peroxisomal tetrameric carbonyl reductase.
Dog liver contains an oligomeric NADPH-dependent carbonyl reductase (CR) with substrate specificity for alkyl phenyl ketones, but its endogenous substrate and primary structure remain unknown. In this study, we examined the molecular weight and substrate specificity of the enzyme purified from dog liver. The enzyme is a ca. 100-kDa tetramer composing of 27-kDa subunit, and reduces all-trans-retinal and alpha-dicarbonyl compounds including isatin, which are substrates for pig peroxisomal tetrameric carbonyl reductase (PTCR). In addition, the dog enzyme resembles pig PTCR in inhibitor sensitivity to flavonoids, myristic acid, lithocholic acid, bromosulfophthalein and flufenamic acid. Furthermore, the amino acid sequence of dog CR determined by protein sequencing and cDNA cloning was 84% identical to that of pig PTCR and had a C-terminal peroxisomal targeting signal type 1, Ser-His-Leu. The immunoprecipitation using the anti-pig PTCR antibody shows that the dog enzyme is a major form of soluble NADPH-dependent all-trans-retinal reductase in dog liver. Thus, dog oligomeric CR is PTCR, and may play a role in retinoid metabolism as a retinal reductase.
Endo
Satoshi
S
Laboratory of Biochemistry, Gifu Pharmaceutical University, Mitahora-higashi, Gifu 502-8585, Japan. sendo@gifu-pu.ac.jp
Matsunaga
Toshiyuki
T
Nagano
Makoto
M
Abe
Hiroko
H
Ishikura
Syuhei
S
Imamura
Yorishige
Y
Hara
Akira
A
D000429:Alcohol Oxidoreductases / Q000235:genetics / Q000378:metabolism*; D000595:Amino Acid Sequence; D000818:Animals; D015153:Blotting, Western; D017931:DNA Primers; D018076:DNA, Complementary / Q000096:biosynthesis / Q000302:isolation & purification; D004285:Dogs; D008099:Liver / Q000201:enzymology*; D008297:Male; D008969:Molecular Sequence Data; D020675:Peroxisomes / Q000201:enzymology*; D011994:Recombinant Proteins / Q000096:biosynthesis; D012176:Retinoids / Q000494:pharmacology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013552:Swine; D014018:Tissue Distribution