Carbonyl Reductase Activity Exhibited by Pig Testicular 20β-Hydroxysteroid Dehydrogenase

The carbonyl reductase activity exhibited by pig testicular 20β-hydroxysteroid dehydrogenase (20β-HSD) was examined using a recombinant enzyme. Kinetic parameters were obtained for 48 carbonyl group-containing substrates, including aromatic aldehydes, aromatic ketones, cycloketones, quinones, alipha...

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Bibliographic Details
Published in:Biological & pharmaceutical bulletin 1997/11/15, Vol.20(11), pp.1215-1218
Main Authors: NAKAJIN, Shizuo, TAMURA, Fumihiro, TAKASE, Noriko, TOYOSHIMA, Satoshi
Format: Article
Language:English
Subjects:
20-Hydroxysteroid Dehydrogenases - metabolism
20β-hydroxysteroid dehydrogenase
Analytical, structural and metabolic biochemistry
Animals
Biological and medical sciences
carbonyl reductase
Chromatography, High Pressure Liquid
Electrophoresis, Polyacrylamide Gel
Enzymes and enzyme inhibitors
Fundamental and applied biological sciences. Psychology
kinetics
Male
Oxidoreductases
Oxidoreductases - metabolism
pig
recombinant enzyme
Recombinant Proteins - metabolism
Swine
testis
Testis - enzymology
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Summary:The carbonyl reductase activity exhibited by pig testicular 20β-hydroxysteroid dehydrogenase (20β-HSD) was examined using a recombinant enzyme. Kinetic parameters were obtained for 48 carbonyl group-containing substrates, including aromatic aldehydes, aromatic ketones, cycloketones, quinones, aliphatic aldehydes and aliphatic ketones. 20β-HSD showed a high affinity towards quinones, such as 9, 10-phenanthrenequinone, α-naphthoquinone and menadione (Km values of 4, 2 and 5 μM, respectively), and the substrate utilization efficiency (Vmax/Km) of the enzyme against these quinones was very high. Cyclohexanone and 2-methylcyclohexanone were also reduced with a high Vmax/Km value, but not cyclopentanone or 2-methylcyclopentanone. Various aromatic aldehydes and ketones including benzaldehyde- and acetophenone-derivatives were reduced by 20β-HSD. Especially, 4-nitrobenzaldehyde and 4-nitroacetophenone were reduced with high Vmax/Km values in related compounds. The enzyme also reduced the pyridine-derivatives, 2-, 3-, and 4-benzoylpyridine, with the Vmax/Km value for 2-benzoylpyridine being the highest. 20β-HSD reduced aliphatic aldehydes and aliphatic ketones, but was more effective on the former. The correlation between the structure of carbonyl compounds and their substrate Vmax/Km is discussed.
ISSN:0918-6158
1347-5215
DOI:10.1248/bpb.20.1215