Activation of purified cytoplasmic 17 beta-hydroxysteroid dehydrogenase from human placenta by human albumin and globulin.
The cytoplasmic 17 beta-hydroxysteroid dehydrogenase of human placenta, purified more than 2500-fold, was activated by small amounts of human albumin and globulin. This activation was dependent on substrate concentration. At 20 microM estradiol (10 X KM) and two different concentrations of enzyme (0.01 and 2 micrograms/ml), the activation was greatest at albumin or globulin concentrations between 0 and 30 micrograms/ml. At "low" concentrations of estradiol (20 nM = 10(-2) X KM) and enzyme (0.01 microgram/ml), maximal activity occurred at approximately 10 micrograms/ml. Higher concentrations of albumin and globulin led to a decline in activity.
D015067:17-Hydroxysteroid Dehydrogenases / Q000378:metabolism*; D003593:Cytoplasm / Q000201:enzymology; D004789:Enzyme Activation / Q000187:drug effects; D005260:Female; D006801:Humans; D007700:Kinetics; D010920:Placenta / Q000201:enzymology*; D011247:Pregnancy; D012709:Serum Albumin / Q000494:pharmacology*; D012712:Serum Globulins / Q000494:pharmacology*
D012709:Serum Albumin; D012712:Serum Globulins; D015067:17-Hydroxysteroid Dehydrogenases