Radiation aggregates of insulin.

During the irradiation of aqueous solution of insulin (pH 1.8) the decrease of original insulin molecules and the formation of radiation aggregates of insulin was studied in dependence on the concentration of irradiation solution, on the doses and conditions of irradiation (oxygenated and oxygen-free atmosphere, the presence of t-butanol, addition of [14C]amino acids). From the results obtained and results published earlier it may be assumed that in irradiated solution on insulin new covalent bonds between insulin molecules are formed at tyrosyl, phenylalanyl and cystyl radicals; these radicals are formed by the action of both direct and indirect effect (at present pH 1.8 mainly of H atoms).