17 beta-hydroxysteroid dehydrogenase activity in canine pancreas.
The mitochondrial fraction of the dog pancreas showed NAD(H)-dependent enzyme activity of 17 beta-hydroxysteroid dehydrogenase. The enzyme catalyzes oxidoreduction between androstenedione and testosterone. The apparent Km value of the enzyme for androstenedione was 9.5 +/- 0.9 microM, the apparent Vmax was determined as 0.4 nmol mg-1 min-1, and the optimal pH was 6.5. In phosphate buffer, pH 7.0, maximal rate of androstenedione reduction was observed at 37 degrees C. The oxidation of testosterone by the enzyme proceeded at the same rate as the reduction of the androstenedione at a pH of 6.8-7.0. The apparent Km value and the optimal pH of the enzyme for testosterone were 3.5 +/- 0.5 microM and 7.5, respectively.
Mendoza-Hernández
G
G
Departamento de Bioquímica, Facultad de Medicina, Universidad Nacional Autónoma de México, D. F., Mexico.
López-Solache
I
I
Rendón
J L
JL
Díaz-Sánchez
V
V
Díaz-Zagoya
J C
JC
D015067:17-Hydroxysteroid Dehydrogenases / Q000378:metabolism*; D000735:Androstenedione / Q000378:metabolism; D000818:Animals; D004285:Dogs; D007700:Kinetics; D008297:Male; D010179:Pancreas / Q000201:enzymology*; D013347:Subcellular Fractions / Q000201:enzymology; D013739:Testosterone / Q000378:metabolism; D013816:Thermodynamics; D014316:Tritium
D014316:Tritium; D013739:Testosterone; D000735:Androstenedione; D015067:17-Hydroxysteroid Dehydrogenases; C032690:3-alpha-(17-beta)-hydroxysteroid dehydrogenase (NAD(+))