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Lactoylglutathione lyase

About: Lactoylglutathione lyase is a(n) research topic. Over the lifetime, 771 publication(s) have been published within this topic receiving 35158 citation(s). The topic is also known as: GLOD1 & GLYI.

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Book ChapterDOI
TL;DR: The sum of the reduced and oxidized forms of glutathione can be determined by using a kinetic assay in which catalytic amounts of GSH or GSSG and glutATHione reductase bring about the continuous reduction of 5,5′-dithiobis(2-nitrobenzoic acid) (DTNB) by nicotinamide adenine dinucleotide phosphate (NADPH).

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Abstract: Publisher Summary This chapter presents the assay of glutathione (GSH), glutathione disulfide (GSSG), and glutathione mixed disulfides (GSSR). The sum of the reduced and oxidized forms of glutathione can be determined by using a kinetic assay in which catalytic amounts of GSH or GSSG and glutathione reductase bring about the continuous reduction of 5,5′-dithiobis(2-nitrobenzoic acid) (DTNB) by nicotinamide adenine dinucleotide phosphate (NADPH). The sensitivity of the assay may be enhanced by measuring NADPH fluorometrically. There are other two enzymatic assay available. In the first assay, the formation of the reduced glutathione using glyoxalase I can be monitored directly at 240 nm, or at very low levels of GSH, a dual wavelength spectrophotometer can be used at the wavelength-pair 240–270 nm with the same extinction coefficient. The second assay involves O-phthaldialdehyde, which forms a fluorescent complex with GSH and can be monitored at 350 nm–420 nm.

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1,466 citations


Journal ArticleDOI
02 Apr 2012-Journal of Botany
TL;DR: The aim of this review is to integrate a recent understanding of physiological and biochemical mechanisms of HM-induced plant stress response and tolerance based on the findings of current plant molecular biology research.

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Abstract: Heavy metal (HM) toxicity is one of the major abiotic stresses leading to hazardous effects in plants. A common consequence of HM toxicity is the excessive accumulation of reactive oxygen species (ROS) and methylglyoxal (MG), both of which can cause peroxidation of lipids, oxidation of protein, inactivation of enzymes, DNA damage and/or interact with other vital constituents of plant cells. Higher plants have evolved a sophisticated antioxidant defense system and a glyoxalase system to scavenge ROS and MG. In addition, HMs that enter the cell may be sequestered by amino acids, organic acids, glutathione (GSH), or by specific metal-binding ligands. Being a central molecule of both the antioxidant defense system and the glyoxalase system, GSH is involved in both direct and indirect control of ROS and MG and their reaction products in plant cells, thus protecting the plant from HM-induced oxidative damage. Recent plant molecular studies have shown that GSH by itself and its metabolizing enzymes—notably glutathione S-transferase, glutathione peroxidase, dehydroascorbate reductase, glutathione reductase, glyoxalase I and glyoxalase II—act additively and coordinately for efficient protection against ROS- and MG-induced damage in addition to detoxification, complexation, chelation and compartmentation of HMs. The aim of this review is to integrate a recent understanding of physiological and biochemical mechanisms of HM-induced plant stress response and tolerance based on the findings of current plant molecular biology research.

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669 citations


Journal ArticleDOI
01 Feb 1995-Aquatic Toxicology
Abstract: The effects of exposure to metals under and laboratory conditions were investigated in the Mediterranean mussel Mytilus galloprovincialis. The examined biological responses included the concentrations of heavy metals, the level of glutathione, and the activity of several enzymes selected among glutathione-dependent oxidoreductases and hydrolases: glutathione reductase. EC1.6.4.2; glyoxalase I, EC4.4.1.5; glyoxalase II, EC3.1.2.6; glutathione S-transferases, EC2.5.1.18; Se-dependent, EC1 11.1.9 and Se-independent, EC2.5.1.18 glutathione peroxidases; catalase, EC1.11.1.6; superoxide dismutase, EC1.15.1.1; alkaline phosphatase, EC3.1.3.1; cholinesterase, EC3.1.1.8; arylesterases, EC3.1.1.2. The analyses were carried out on digestive gland and gills of mussels from two populations, respectively from a polluted and a clean site. The same parameters were measured in control mussels transplanted to the polluted environment, and in molluscs exposed to copper under laboratory conditions. The comparison between different field and laboratory exposures was expected to give useful indications for a proper use of biochemical responses as biomarkers in monitoring trace metal pollution. Compared to control mussels, the polluted ones (native, transplanted and copper-exposed) showed significantly lower levels of glutathione and higher activities of the glyoxalases (which detoxify reactive α-ketoaldehydes formed in cellular oxidative processes). On the other hand, native mussels from both the polluted and control populations exhibited similar enzymatic activities of glutathione reductase, glutathione peroxidases, catalase, superoxide dismutase and alkaline phosphatase, whereas, in both transplanted and copper-exposed mussels, these enzymes showed significant variations. This finding could suggest the occurrence of some adaptation or compensatory mechanism in chronically polluted organisms. No clear results were obtained with glutathione S-transferases, whereas arylesterases and cholinesterases appeared not to be affected by metal pollution. From the results, three different kind of biological responses were identified and the implications for ecotoxicological studies discussed.

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594 citations


Journal ArticleDOI
Paul J. Thornalley1Institutions (1)
TL;DR: Glyoxalase I has a critical role in the prevention of glycation reactions mediated by methylglyoxal, glyoxal and other alpha-oxoaldehydes in vivo and is particularly important in diabetes and uraemia.

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Abstract: Glyoxalase I is part of the glyoxalase system present in the cytosol of cells. The glyoxalase system catalyses the conversion of reactive, acyclic alpha-oxoaldehydes into the corresponding alpha-hydroxyacids. Glyoxalase I catalyses the isomerization of the hemithioacetal, formed spontaneously from alpha-oxoaldehyde and GSH, to S -2-hydroxyacylglutathione derivatives [RCOCH(OH)-SG-->RCH(OH)CO-SG], and in so doing decreases the steady-state concentrations of physiological alpha-oxoaldehydes and associated glycation reactions. Physiological substrates of glyoxalase I are methylglyoxal, glyoxal and other acyclic alpha-oxoaldehydes. Human glyoxalase I is a dimeric Zn(2+) metalloenzyme of molecular mass 42 kDa. Glyoxalase I from Escherichia coli is a Ni(2+) metalloenzyme. The crystal structures of human and E. coli glyoxalase I have been determined to 1.7 and 1.5 A resolution. The Zn(2+) site comprises two structurally equivalent residues from each domain--Gln-33A, Glu-99A, His-126B, Glu-172B and two water molecules. The Ni(2+) binding site comprises His-5A, Glu-56A, His-74B, Glu-122B and two water molecules. The catalytic reaction involves base-catalysed shielded-proton transfer from C-1 to C-2 of the hemithioacetal to form an ene-diol intermediate and rapid ketonization to the thioester product. R - and S-enantiomers of the hemithioacetal are bound in the active site, displacing the water molecules in the metal ion primary co-ordination shell. It has been proposed that Glu-172 is the catalytic base for the S-substrate enantiomer and Glu-99 the catalytic base for the R-substrate enantiomer; Glu-172 then reprotonates the ene-diol stereospecifically to form the R-2-hydroxyacylglutathione product. By analogy with the human enzyme, Glu-56 and Glu-122 may be the bases involved in the catalytic mechanism of E. coli glyoxalase I. The suppression of alpha-oxoaldehyde-mediated glycation by glyoxalase I is particularly important in diabetes and uraemia, where alpha-oxoaldehyde concentrations are increased. Decreased glyoxalase I activity in situ due to the aging process and oxidative stress results in increased glycation and tissue damage. Inhibition of glyoxalase I pharmacologically with specific inhibitors leads to the accumulation of alpha-oxoaldehydes to cytotoxic levels; cell-permeable glyoxalase I inhibitors are antitumour and antimalarial agents. Glyoxalase I has a critical role in the prevention of glycation reactions mediated by methylglyoxal, glyoxal and other alpha-oxoaldehydes in vivo.

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560 citations


Journal ArticleDOI
Paul J. Thornalley1Institutions (1)
TL;DR: The modification of nucleic acids and protein by methylglyoxal is a signal for their degradation and may have a role in the development of diabetic complications, atherosclerosis, the immune response in starvation, aging and oxidative stress.

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Abstract: 1. Methylglyoxal is a reactive alpha-oxoaldehyde and physiological metabolite formed by the fragmentation of triose-phosphates, and by the metabolism of acetone and aminoacetone. 2. Methylglyoxal modifies guanylate residues to form 6,7-dihydro-6,7-dihydroxy-6-methyl-imidazo[2,3-b]purine-9(8)one and N2-(1-carboxyethyl)guanylate residues and induces apoptosis. 3. Methylglyoxal modifies arginine residues in proteins to form N(delta)-(4,5-dihydroxy-4-methylimidazolidin-2-yl) ornithine, N(delta)-(5-hydro-5-methylimidazol-4-on-2-yl)ornithine and N(delta)-(5)methylimidazol-4-on-2-yl)ornithine residues. 4. Methylglyoxal-modified proteins undergo receptor-mediated endocytosis and lysosomal degradation in monocytes and macrophages, and induce cytokine synthesis and secretion. 5. Methylglyoxal is detoxified by the glyoxalase system. Decreased detoxification of methylglyoxal may be induced pharmacologically by glyoxalase I inhibitors which have anti-tumor and anti-malarial activities. 6. The modification of nucleic acids and protein by methylglyoxal is a signal for their degradation and may have a role in the development of diabetic complications, atherosclerosis, the immune response in starvation, aging and oxidative stress.

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538 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202119
202028
201919
201823
201730
201635

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Topic's top 5 most impactful authors

Bengt Mannervik

36 papers, 1.5K citations

Paul J. Thornalley

35 papers, 4.4K citations

Masayuki Fujita

30 papers, 3.6K citations

Mirza Hasanuzzaman

26 papers, 2.5K citations

Kamrun Nahar

17 papers, 1.2K citations