A reinvestigation of inhibitors of glyoxalase I
TL;DR: It is found that nucleotides such as ATP, GTP and different classes of other reagents based on transition state analogy (D-isoascorbate, dihydroxyfumaric acid, rhodizonic acid) do not inhibit yeast or goat liver glyoxalase I.
Abstract: It has been reported earlier that nucleotides, nucleosides and a series of structurally related compounds as well as compounds based on transition state analogy inhibit yeast glyoxalase I. In our study on the metabolic regulation of glyoxalase I, we have found that nucleotides such as ATP, GTP and different classes of other reagents based on transition state analogy (D-isoascorbate, dihydroxyfumaric acid, rhodizonic acid) do not inhibit yeast or goat liver glyoxalase I. The reported inhibition of glyoxalase I by these compounds has been found to be due to the interference of these compounds with the absorbancy at 240 nm of S-D-lactoylglutathione formed by the glyoxalase I reaction.
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TL;DR: Examination of some of the aforementioned compounds has revealed that squaric acid does not function as an inhibitor of glyoxalase I and several other compounds are much less effective in this regard than previously reported.
8 citations
TL;DR: In this article, the authors demonstrate the inhibitory effect of 3, 3'-[3-(5-chloro-2-hydroxyphenyl)-3-oxopropane-1, 1-diyl] Bis (4-hydroxycoumarin) on the glyoxalase system, and indirectly its anticancer activity.
2 citations
TL;DR: The results indicate that D, and L-lactaldehyde are strong non-competitive inhibitors of glyoxalase I and the effect with the D-isomer is more pronounced, whereas both D,L-glyceraldehyde and acetaldehyde are moderately inhibitory and the nature of inhibition is strictly competitive.
Abstract: The possible effect of several physiologically important aldehydes has been tested on partially purified glyoxalase I of Ehrlich ascites carcinoma (EAC) cells. The results indicate that D, and L-lactaldehyde are strong non-competitive inhibitors of glyoxalase I and the effect with the D-isomer is more pronounced, whereas both D,L-glyceraldehyde and acetaldehyde are moderately inhibitory and the nature of inhibition is strictly competitive. Moreover, D,L-glyceraldehyde strongly inhibits the utilization of methylglyoxal by intact EAC cells. A search for the presence of several aldehyde metabolizing enzymes in EAC cells indicates that non-specific aldehyde reductase, methylglyoxal reductase, aldehyde dehydrogenase and alcohol dehydrogenase are apparently absent in this rapidly growing, highly de-differentiated malignant cell.
1 citations
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TL;DR: The turbidity produced when protein is mixed with low concentrations of any of the common protein precipitants can be used as an index of protein concentration, and this advantage is used to eliminate the interference of nucleic acids in the estimation of protein.
Abstract: Publisher Summary The turbidity produced when protein is mixed with low concentrations of any of the common protein precipitants can be used as an index of protein concentration. The resulting turbidity is maximum after about 10 minutes and may be measured spectrophotometrically in the wavelength region of 600 m. Standardization may be effected by comparison with the turbidity produced by a suspension of a dried protein precipitate, or reference may be had to the methyl acrylate-styrene polymer. Turbidimetric techniques are rapid and convenient, but they yield different values with different proteins. They do not permit differentiation between protein and acid-insoluble compounds such as nucleic acids. Protein estimation with the Folin-Ciocalteu reagent include (1) biuret reaction of protein with copper ion in alkali, and (2) reduction of the phosphomolybdic-phosphotungstic reagent by the tyrosine and tryptophan present in the treated protein. Protein estimation by ultraviolet absorption takes advantage of the fact that nucleic acid, however, absorbs much more strongly at 260 mμ than at 280 mμ, whereas with protein the reverse is true. This advantage is used to eliminate, by calculation, the interference of nucleic acids in the estimation of protein.
3,391 citations
"A reinvestigation of inhibitors of ..." refers methods in this paper
...Protein was estimated by the method of either Warburg and Christian or that of Lowry et al. as described by Layne (1957)....
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TL;DR: In this communication, a method is described which utilizes the reaction of acyl phosphates with hydroxylamine and the acyl part of the acid anhydride is converted into hydroxamic acid.
1,373 citations
"A reinvestigation of inhibitors of ..." refers methods in this paper
...Glyoxalase I was assayed by monitoring the formation of S-D-lactoylglutathione, which was measured by its absorbance at 240 nm or colorimetrically by the hydroxylamine-ferric chloride colour reaction method (Lipmann and Tuttle, 1945) as used for the assay of thioesters (Racker, 1952)....
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538 citations
"A reinvestigation of inhibitors of ..." refers background in this paper
...The glyoxalase system consists of two enzymes, glyoxalase Ι (EC 4·4·1·5) and glyoxalase II (EC 3· 1·2·6) (Racker, 1951), Glyoxalase I acts upon GSH and methylglyoxal (and other á6-ketoaldehydes) to produce S-D-lactoylglutathione....
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TL;DR: It is proposed that methylglyoxal synthase and glyceraldehyde 3-phosphate dehydrogenase play important roles in the catabolism of the triose phosphates in E. coli and channelling of dihydroxyacetone phosphate via methyl Glyoxal would not be linked to ATP formation and could be involved in the uncoupling of catabolist and anabolism.
Abstract: 1. Methylglyoxal synthase was purified over 1500-fold from glycerol-grown Escherichia coli K 12 strain CA 244. The purified enzyme was inactivated by heat or proteolysis, had a molecular weight of approx. 67000, a pH optimum of 7.5 and was specific for dihydroxyacetone phosphate with Km 0.47mm. 2. The possibility that a Schiff-base intermediate was involved in the reaction mechanism was investigated but not confirmed. 3. The purified enzyme lost activity, especially at low temperature, but could be stabilized by Pi. Two binding sites for Pi may be present on the enzyme. Of other compounds tested only the substrate, dihydroxyacetone phosphate, and bovine serum albumin showed any significant stabilizing effect. 4. Phosphoenolpyruvate, 3-phosphoglycerate, PPi and Pi were potent inhibitors of the enzyme. Kinetic experiments showed that PPi was apparently a simple competitive inhibitor, but inhibition by the other compounds was more complex. In the presence of Pi the enzyme behaved co-operatively, with at least three binding sites for dihydroxyacetone phosphate. 5. It is proposed that methylglyoxal synthase and glyceraldehyde 3-phosphate dehydrogenase play important roles in the catabolism of the triose phosphates in E. coli. Channelling of dihydroxyacetone phosphate via methylglyoxal would not be linked to ATP formation and could be involved in the uncoupling of catabolism and anabolism.
118 citations
"A reinvestigation of inhibitors of ..." refers background in this paper
...The enzymes responsible for the formation of methylglyoxal have been purified from several sources (Hopper and Cooper, 1972; Ray and Ray, 1981, 1983, 1987; Murata et al., 1985)....
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TL;DR: A study of a series of S-alkylglutathiones as inhibitors of the enzyme, glyoxalase I, revealed that a non-polar region exists on the enzyme which plays an important role in the formation of an enzyme-inhibitor complex.
105 citations
"A reinvestigation of inhibitors of ..." refers background or methods or result in this paper
...However the S-alkyl glutathiones served as controls and appeared to be true inhibitors of glyoxalase I as reported earlier (Vince and Wadd, 1969)....
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...S-Alkyl glutathiones were also found to be strong competitive inhibitors of glyoxalase I (Vince and Wadd, 1969; Vince et al., 1973; Lyon and Vince, 1977)....
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...Based on these assumptions GSH analogues have been synthesized and used as inhibitors of glyoxalase I (Vince and Wadd, 1969; Vince et al., 1973; Lyon and Vince, 1977)....
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