Showing papers on "Methylglyoxal published in 1991"
01 Jan 1991
168 citations
TL;DR: In this article, the UV-visible absorption spectrum of methylglyoxal was measured by conventional UV spectroscopic techniques (220-490 nm) and in separate experiments in which gas phase methylglyoxide was produced is situ by the chlorine-atom-initiated oxidation of acetol (390-470 nm).
Abstract: The UV-visible absorption spectrum of methylglyoxal was measured by conventional UV spectroscopic techniques (220–490 nm) and in separate experiments in which gas phase methylglyoxal was produced is situ by the chlorine-atom-initiated oxidation of acetol (390–470 nm). In the region where the two sets of results overlap, reasonably good agreement is observed. These results indicate considerably high cross-sections than those previously reported in the literature.
55 citations
47 citations
TL;DR: In the presence of lactaldehyde, a catabolite of MG, the inhibitory effect of MG on the respiration of tumor cells was significantly reduced and lactaldehyde can exert a similar protective effect on the loss of viability and transplantability of MG‐treated EAC cells.
Abstract: The effect of methylglyoxal (MG), ascorbic acid and lactaldehyde has been tested on the in vitro respiration of Ehrlich ascites carcinoma (EAC) cells and several normal and malignant human tissues. Methylglyoxal inhibited the respiration of each type of malignant cell and tissue tested, but it had practically no inhibitory effect on the respiration of any of the normal cells and tissues. Ascorbic acid exhibited a synergistic effect with MG in inhibiting the respiration of all the neoplastic cells. In the presence of lactaldehyde, a catabolite of MG, the inhibitory effect of MG on the respiration of tumor cells was significantly reduced. Lactaldehyde can exert a similar protective effect on the loss of viability and transplantability of MG-treated EAC cells.
41 citations
TL;DR: The glyoxalase I was purified from Brassica juncea by affinity chromatography on S‐hexyl GSH sepharose 4B and magnesium was found to stimulate the enzyme activity.
36 citations
TL;DR: It is assumed that the increased oxidation of aniline hydroxylase combined with decreased glutathione levels after methylglyoxal treatment favours the formation of potentially hazardous phenol derivatives in the liver.
33 citations
TL;DR: The method described provides a reliable, large-scale procedure for the preparation and purification of S-acylglutathiones of increasing biological and pharmacological interest.
Abstract: S-2-Hydroxyacylglutathione derivatives have been prepared by enzymatic synthesis from α-oxo aldehydes and reduced glutathione in the presence of glyoxalase I. S-D-Lactoylglutathione, S-D-mandelylglutathione, S-glycolylglutathione and S-L-glyceroylglutathione were prepared from methylglyoxal, phenylglyoxal, glyoxal and hydroxypyruvaldehyde, respectively. They were purified by ion exchange chromatography on Dowex 1 on a gram scale. Analytical data and re-evaluated extinction coefficients for these compounds are presented.The method described provides a reliable, large-scale procedure for the preparation and purification of S-acylglutathiones of increasing biological and pharmacological interest.
29 citations
TL;DR: An enzyme which catalyzes the reduction of 3- deoxyglucosone to 3-deoxyfructose and methylglyoxal to acetol, was isolated and purified from porcine liver and inhibited the advanced stage of the Maillard reaction.
Abstract: An enzyme which catalyzes the reduction of 3-deoxyglucosone to 3-deoxyfructose and methylglyoxal to acetol, was isolated and purified from porcine liver. 2-Oxoaldehyde compounds were found to be especially good substrates and monocarbonyl compounds were poor substrates for this reductase. The optimum pH of the enzyme activity was 6.5. The Km for 3-deoxyglucosone and methylglyoxal were 2.1 mM and 3.3 mM, respectively. The enzyme consisted of a single polypeptide chain with a molecular mass of 38 kDa. The activity of the enzyme was completely inhibited by p-chloromercuribenzoate. The enzyme inhibited the advanced stage of the Maillard reaction.
29 citations
TL;DR: It is assumed that methylglyoxal has contrasting effects in hepatocytes, and can contribute to the disturbed metabolism under circumstances when the acetone production is elevated.
29 citations
TL;DR: Methylglyoxal (a dicarbonyl which is analogous to hydroxypyruvaldehyde derived from glyceraldehyde autoxidation) proved to have a powerful inhibitory action on ATPase activities, suggesting that the sulphydryl groups of the active site of the enzyme are the critical targets for dicARBonyl compounds.
21 citations
TL;DR: The glyoxalase-2-deficient red cells were used to test whether S-lactoylglutathione is transported from red cells via the glutathione-S-conjugate transporter; this transport appeared not to occur.
TL;DR: Glyoxalase I was purified from Hansenula mrakii IFO 0895 which was resistant to 25 mM methylglyoxal and the activity of the enzyme was not inhibited by metal ion chelators such as EDTA, which is a potent inhibitor for glyoxal enzyme Is from other sources.
TL;DR: Bothabolic and antiproliferative effects of methylglyoxal bis(butylamidinohydrazone) (MGBB) and MGBCP, inhibitors for polyamine biosynthetic pathway, on Escherichia coli, Shigella sonnei, Aeromonas sobria,aeromonas hydrophila and Vibrio cholerae were investigated.
Abstract: Metabolic and antiproliferative effects of methylglyoxal bis(butylamidinohydrazone) (MGBB) and methylglyoxal bis(cyclopentylamidinohydrazone) (MGBCP), inhibitors for polyamine biosynthetic pathway, on Escherichia coli, Shigella sonnei, Aeromonas sobria, Aeromonas hydrophila and Vibrio cholerae were investigated. MGBB at the concentration of 100 mumol/l depleted intracellular putrescine and spermidine concentrations of E. coli to 25 and 20% of the controls, respectively, while MGBCP depressed their concentrations to 38 and 24%, respectively. In these polyamine-depleted E. coli cells the syntheses of RNA, DNA and protein decreased to 13, 54 and 29% of the control, respectively, with MGBB and to 23, 71 and 55%, respectively, with MGBCP. The minimum inhibitory concentrations (MIC) of MGBB for the growth of A. sobria, E. coli, A. hydrophila, V. cholerae and Sh. sonnei were estimated to be 50, 160, 240, 285 and 320 mumol/l, respectively, whereas those of MGBCP were slightly higher for respective bacteria.
TL;DR: The reductase which catalyzes the reduction of 3-DG to 3-DF and MG to acetol, was purified and characterized from porcine kidney, which is speculated to prevent the advanced stage of the Maillard reaction as a self-defense enzyme.
Abstract: In order to verify the formation of endogenous 3-deoxyglucosone (3-DG), an intermediate compound in the Maillard reaction, we tried to detect 3-deoxyfructose (3-DF) which is main metabolite of 3-DG. Endogenous 3-DF was detected in the urine of normal and diabetic rats by the oral administration of 3-DG-free feed. Metabolizing activities of crude extracts prepared from porcine organs were examined using methylglyoxal (MG) and 3-DG as substrates. NAD- or NADP-dependent 2-oxoaldehyde dehydrogenase activity was detected in liver, kidney, small intestine and lung. On the other hand, NADH- or NADPH-dependent 2-oxoaldehyde reductase activity was detected in all porcine organs in which liver and kidney contained higher activity of NADPH-dependent enzyme than the other organs. The reductase which catalyzes the reduction of 3-DG to 3-DF and MG to acetol, was purified and characterized from porcine kidney. The enzyme was the same to NADPH-dependent-2-oxoaldehyde reductase from porcine liver, which is speculated to prevent the advanced stage of the Maillard reaction as a self-defense enzyme.
TL;DR: Human red blood cell glyoxalase I has a rel mol mass of 46 kDa and an isoelectric point of 4.8 and is a dimer of two identical or similar subunits, representing the homozygous and heterozygous expression of a 2 allelic gene, GLO’ and GL02.
TL;DR: Methylglyoxal reductase was purified from Hansenula mrakii IFO 0895 to a homogenous state on polyacrylamide gel electrophoresis and the activity of the enzyme was inhibited by p -chloromercuribenzoate and HgCl 2.
TL;DR: It would appear that relatively low concentrations of methylglyoxal can selectively enhance beta-adrenoceptor- and inhibit alpha(2)-adrenOceptor-mediated responses.
Journal Article•
TL;DR: The enzymes which metabolize 2-oxoaldehyde compounds in a crude extract of chicken liver were examined using 3-deoxyglucosone (3-DG) and methylglyoxal (MG) and NADH- and NADPH-dependent reductase activities were observed and the latter was more than the former.
Abstract: The enzymes which metabolize 2-oxoaldehyde compounds in a crude extract of chicken liver were examined using 3-deoxyglucosone (3-DG) and methylglyoxal (MG). NADH- and NADPH-dependent reductase activities were observed and the latter was more than the former.NADPH-dependent 2-oxoaldehyde reductase was purified from chicken liver by ammonium sulfate fractionation, and DEAE-cellulose, CM-cellulose, hydroxylapatite, and Sephadex G-100 column chromatographies. The molecular weight of the enzyme was estimated to be 38,000 and 32,000 by SDS-PAGE and gel filtration, respectively. The optimum pH was 6.5–7.0 and this enzyme was stable at pH 7.0–8.0. The Km for 3-DG and MG were 3.75 mm and 1.52 mm, respectively. This enzyme had high activities towards 2-oxoaldehyde compounds, such as 3-DG, MG, and phenylglyoxal. This enzyme converted 3-deoxyglucosone (3-DG) to 3-deoxyfructose, and methylglyoxal (MG) to acetol.