PubMedDate not supplied
Comparative study of iodination of chymotrypsin and trypsin was carried out using either iodine monochloride or the electrochemical procedure under conditions of controlled anode potential. It was shown that a part of iodine monochloride was consumed for oxidation of protein molecules. As a result of this process specific activity of the enzymes was decreased down to 50-60% of the initial activity after introduction of 2 atoms of iodine per a molecule. The similar degree of iodination under mild conditions of electrolysis in potentiostatic experiments caused considerably lower decrease in the enzymatic activity, reaching 5-10% of the initial activity (after introduction of I atom of iodine per a molecule--2.5%); labelling of trypsin and chymotrypsin by means of iodine radionuclides is promising for various medico-biological purposes.