[Effect of detergents on the solubilization of 5'-nucleotidase from the thyroid gland]

The effect of Triton X-100, sodium deoxycholate and saponin upon the solubilization of 5'-nucleotidase, the membrane enzyme derived from pig thyroid was studied. Triton X-100 at the concentration of 0.1% did not cause enzyme solubilization, whereas at the concentration of 1.0% it caused only partial release of the former from the membranes. Saponin (1.0% concentration) brought about a marked (about threefold) increase in the enzyme activity which resulted from the exposing active loci of the enzyme, however it did not cause total solubilization of it. 1% sodium deoxycholate increased the enzyme activity by 5 times and also caused its almost total solubilization (over 90%). The results indicate the 5'-nucleotidase is strongly bound to the cell membranes and the non-ionic detergents like Triton X-100 and saponin do not fit for the solubilization of this enzyme.