Effect of fatty acid binding on the glycation of human serum albumin

Fructosamine quantification, tryptophan fluorescence, and tandem mass spectrometry were used to investigate the effect of fatty acid binding on the glycation of human serum albumin (HSA). Fructosamine quantification evidenced that linoleic, oleic, and palmitic acids had an inhibitory effect on the glycation of HSA at the 48 and 96 hour incubations and a facilitating effect at 168 hours. Tryptophan fluorescence spectroscopy revealed that initially glycation and fatty acid binding have similar secondary structural changes, but longer glycation incubations resulted in more overall quenching of relative intensities when compared to HSA. Tandem mass spectrometry substantiated that as incubation time increases the number of possible glycation sites increased for all treatments. Upon fatty acid binding, lysines within the central channel of HSA become glycated, while glycated HSA had no central channel glycation sites. Although initially inhibiting glycation, fatty acids facilitate glycation throughout the protein over time.