Glycine and serine markedly eliminate methylglyoxal in the presence of formaldehyde via the formation of imidazole salts

L-glycine and L-serine are the building blocks of proteins and exhibit various biological activities. This work found that L-glycine and L-serine show low scavenging capacity for methylglyoxal at moderate conditions (pH 7.0, 37 degrees C). However, they efficiently eliminate methylglyoxal and formaldehyde when the two aldehydes co-exist, via generation of imidazole salt, a compound formed by one molecule of methylglyoxal and formaldehyde, and two molecules of amino acids. The imidazole salts were identified in biscuits and fried potato crisps. Moreover, the formation of imidazole salts greatly decreased the cytotoxicity of their precursors, methylglyoxal and formaldehydes. This finding suggests that glycine and serine can be used to scavenge these two harmful aldehydes both after intake and during food processing.