Methylglyoxal

About: Methylglyoxal is a research topic. Over the lifetime, 2844 publications have been published within this topic receiving 102037 citations. The topic is also known as: acetylformaldehyde & pyruvaldehyde.

Methylglyoxal resistance in Bacillus subtilis: contributions of bacillithiol-dependent and independent pathways.

Abstract: Methylglyoxal (MG) is a toxic by-product of glycolysis that damages DNA and proteins ultimately leading to cell death. Protection from MG is often conferred by a glutathione-dependent glyoxalase pathway. However, glutathione is absent from the low-GC Gram-positive Firmicutes, such as Bacillus subtilis. The identification of bacillithiol (BSH) as the major low-molecular-weight thiol in the Firmicutes raises the possibility that BSH is involved in MG detoxification. Here, we demonstrate that MG can rapidly and specifically deplete BSH in cells, and we identify both BSH-dependent and BSH-independent MG resistance pathways. The BSH-dependent pathway utilizes glyoxalase I (GlxA, formerly YwbC) and glyoxalase II (GlxB, formerly YurT) to convert MG to d-lactate. The critical step in this pathway is the activation of the KhtSTU K(+) efflux pump by the S-lactoyl-BSH intermediate, which leads to cytoplasmic acidification. We show that cytoplasmic acidification is both necessary and sufficient for maximal protection from MG. Two additional MG detoxification pathways operate independent of BSH. The first involves three enzymes (YdeA, YraA and YfkM) which are predicted to be homologues of glyoxalase III that converts MG to d-lactate, and the second involves YhdN, previously shown to be a broad specificity aldo-keto reductase that converts MG to acetol.

Glyoxalase I inhibitors in cancer chemotherapy.

Abstract: Several recent developments suggest that the GSH-dependent glyoxalase enzyme system deserves renewed interest as a potential target for antitumour drug development. This summary focuses on the design and development of new classes of tumoricidal agents that specifically target this elementary detoxification pathway in order to induce elevated concentrations of cytotoxic methylglyoxal in tumour cells. Special emphasis is placed on structure- and mechanism-based inhibitors of GlxI (glyoxalase I), the first enzyme in the pathway. A new class of bivalent transition-state analogues is described that simultaneously bind the active site on each subunit of the homodimeric human GlxI, resulting in K (i) values as low as 1 nM. Also described is a new family of bromoacyl esters of GSH that function as active-site-directed irreversible inhibitors of GlxI. Newer prodrugs for delivering the GSH-based inhibitors into tumour cells include reactive sulphoxide esters that undergo acyl exchange with endogenous GSH to give the inhibitors, and polymethacrylamide esters of the inhibitors that are potentially tumour-selective on the basis of the "enhanced permeability and retention effect". Finally, a preliminary evaluation of the efficacy of selected GlxI inhibitors in tumour-bearing mice is given.

A method for the detection of carbonyl compounds in wine: Glyoxal and methylglyoxal

Abstract: Wine aldehydes were identified as O-(2,3,4,5,6-pentafluorobenzyl)-hydroxylamine derivatives by GC-MS or with a GC-electron-capture detector. This method has been used to evaluate levels of glyoxal and methylglyoxal in wine. Reproducibility and linearity studies gave satisfying results. Glyoxal and methylglyoxal are formed during fermentation. Among the factors affecting their production, high musts pH increased the levels found in the corresponding wines. Various microorganisms of the wine such as Saccharomyces cerevisiae and Leuconostoc aenos can produce glyoxal and methylglyoxal. The concentrations in Sherry wines were particularly high. Because of the toxicological properties of these substances, their determination and the knowledge of their metabolism by wine microorganisms are very important.