Electron spin resonance and spectral studies of bovine serum albumin-methylglyoxal complexes

Abstract

Electron spin resonance and spectrophotometric measurements are reported for complexes of bovine serum albumin with methylglyoxal. The optical absorbance at 318 nm was found to be proportional to the unpaired spin concentration of the protein complexes. The constant of proportionality, however, was found to be a sensitive function of the exposure of samples to molecular oxygen, the color of the complexes remaining roughly constant while the spin concentration increased. The relevance of these observations to the previously reported electronic activity of the protein-methylglyoxal complexes is discussed, and a possible mechanism for the electronic decoupling that gives rise to the observed electron spin resonance signal is proposed.