Solubilization of 17 beta-hydroxysteroid dehydrogenase from rat liver microsomes

The conditions for the solubilization of 17 beta-hydroxysteroid dehydrogenase from a rat liver microsomal preparation with the non-ionic detergent Triton X-100 were studied. The recoveries of 17 beta-hydroxysteroid dehydrogenase activity and of proteins in the solubilized form were determined as a function of detergent concentration, of pH and temperature, of incubation time and of saline concentration. The soluble fraction obtained under the optimal conditions contained 80% of the proteins and 75% of the enzymatic activity of initial microsomes. The presence of Triton X-100 in the solubilized proteins was not essential for enzyme activity.