[Free-radical mechanism of antimicrobial action of xanthine oxidase and lactoperoxidase].

The interaction between milk xanthine oxidase (XO) and lactoperoxidase (LP) in model system and antimicrobial action of these enzymes on Escherichia coli 0-111 were studied. It was shown, that bacterial superoxide dismutase (SOD), which transforms O2-. (XO-reaction product) into H2O2 (substrate of LP), is necessary for binding of the reaction sequence: XO-->LP-->antimicrobial products.

[Changes in the fluorescence in preparations of normal human immunoglobulin during deamidation].

It was shown that self-fluorescence of normal human immunoglobulins prepared with the use of donor and placental raw materials lowered after incubation at 37 degrees C for 28 days and after storage under the standard conditions (4-10 degrees C) for 2 years. Dependence of thermostability of the immunoglobulins on the raw material used for their preparation and the storage period was revealed spectrofluorometrically. Resistance of the proteins to thermal denaturation lowered on storage.

[Effect of non-enzymatic desamidation of gamma-globulin on its properties and biological activity].

During incubation of gamma-globulin preparations under conditions similar to physiological ones within 28 days (0.9% NaCl, pH 7.0, 37 degrees) as well as during storage at 3-10 degrees within 36 months gradual nonenzymatic deamidation of the protein occurred mainly due to hydrolysis of readily accessible amide groups (asparagine).