Influence of dicarbonyls on kinetic characteristics of glutathione peroxidase.

Se-containing glutathione peroxidase (GSH-Px) is one of the key enzymes of the body's antioxidant system. The kinetic characteristics of GSH-Px (substrate is tert-butyl hydroperoxide) after modification of the enzyme by various concentrations of natural dicarbonyls (glyoxal, methylglyoxal, malonic dialdehyde) were studied. It was shown that dicarbonyls affected both K and V for GSH-Px. It is suggested that the effect of various dicarbonyls on GSH-Px depends on the molecular mechanisms of their interaction with the amino acid residues of the enzyme.