Nonenzymic, Polyvalent Anion-catalyzed Formation of Methylglyoxal as an Explanation of Its Presence in Physiological Systems

Flavor Development in the Ripening of Anchovy (Engraulis encrasicholus L.)

“…2-Acetyl-1 -pyrroline is unlikely to be a component of fresh anchovy flavor. It was probably formed during the isolation procedure from 1-pyrroline generated by the Strecker degradation of proline (Tressl et al, 1985) and 2-oxopropanal, which has been shown to occur in glycolyzing tissues (Riddle and Lorenz, 1968).…”

Aldehydemetabolism in the cardiovascular system

“…The accumulation of MG in diabetic tissues is associated with the development of cardiovascular, neurological and renal complications. 22,23 Although MG could be formed non-enzymatically from the glycolytic intermediates dihydroxyacetone phosphate and glyceraldehyde or from amine-catalyzed sugar fragmentation, 24,25 it could be generated from other sources as well. Metabolism of acetone during ketosis generates MG, 26 and MG could also be formed enzymatically from aminoacetone via semicarbazide-sensitive amine oxidase, 27 which in diabetic tissue is generated from the catabolism of threonine.…”

Optimization of efficiency in the glyoxalase pathway

“…However, the absence of any clear evidence for allosteric control of the glyoxalase enzymes suggests that the principle function of the pathway is simply to chemically remove cytotoxic methylglyoxal from cells as D-lactate. In mammalian cells, methylglyoxal may arise from several possible sources including the uncatalyzed (Needham & Lehmann, 1937; Riddle & Lorenz, 1968; Richard, 1984) and the triosephosphate isomerase catalyzed (Browne et al, 1976;Cambell et al, 1979) dismutation of intracellular trioses and triose phosphates. In support of a detoxification role for the glyoxalase pathway, a mutant strain of the yeast Saccharomyces cerevisiae, defective in glyoxalase I, is eventually killed by exposure to glycerol and excretes methylglyoxal into the growth medium (Penninckx et al, 1983).…”