[Action of thyroid hormones and somatotropin on the free radical, iron-sulfur protein and cytochrome P-450 state in the liver]. / Vozdeistvie tireoidnykh gormonov i somatotropina na sostoianie svobodnykh radikalov, zhelezosernykh belkov i tsitokhroma P-450 v pecheni.

The state of free radicals, iron-sulphuric proteins and cytochrome P-450 was determined in hypo- and hyperthyroid rats by means of EPR method. It was shown that EPR signal of cytochrome P-450 was increased in the liver of thyroidectomized rats, characterized by somatotropin deficiency and delayed metabolism. It decreased under the action of exogenous somatotropin both in intact and in thyroidectomized animals. Cytochrome P-450 was lowered in hyperthyroid rats, characterized by intensified oxidative processes without signs of the enhanced hepatic growth. The feedback between the intensified hepatic oxidative processes and the activity of cytochrome P-450-dependent multipurposeful oxidases is suggested.

[Stability of Streptomyces griseus carboxypeptidase]. / O stabil'nosti karboksipeptidazy Streptomyces griseus.

Carboxypeptidase of Str. griseus strain 32-13 is stable during storage at a temperature of 10-15 degrees C. Carbohydrates and glycerol in a concentration of 40-80% as well as 0.01 M of L-amino acid prevent the enzyme from thermoinactivation. Anions, such as phosphate, borate, carbonate and acetate, have their inhibitory effect on carboxypeptidase. After the effect of chelate reagents the enzyme activity restores completely only in the presence of Co2+ and partially in the presence of Ni2+ greater than Ca2+ greater than Mn2+ greater than Zn2+.