[The effect of various chemical compounds and storage conditions on the rate of non-enzymatic deamidation of protein preparations].

The effect of different substances partly used as preservatives for the blood storage and at different stages of manufacturing of human blood preparations on the dynamics of nonenzymatic deamidation of commercial protein preparations and on their heat stability was being studied. Albumin and gamma-globulin preparations in the solutions of 60% glycerol, 60% ethylene glycol, 40% beta-alanine, aspartic and glutamic acids in physiological concentrations, 40% glucose and 40% sucrose after 2-hour thermal denaturation (100 degrees) were incubated under (or close to) physiological conditions (pH 7, 37 degrees) for 0.7; 14, 21, 28 and 90 days. The protein preparations in the saline were used as control. After precipitation of protein with TCA, the contents of free ammonia and TCA-soluble products were measured by the Lowry technique. The precipitate washed by organic solvents was used to determine the amide fractions. No reliable difference in increasing the TCA-soluble Folin-positive products was observed. All substances studied but glycerol sped up the deamidation of albumin and gamma-globulin preparations both during thermal denaturation and incubation. On the contrary, glycerol slowed down the deamidation of proteins. Possible reasons of the observed phenomena are discussed.