Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:1.1.1.37 (malate dehydrogenase)
 4,591 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effect of adrenalectomy on the activities of monoamine oxidase (MAO), NADH cytochrome c reductase (NCR), succinate dehydrogenase, malate dehydrogenase, fumarase, NAD+ nucleosidase and acid phosphatase in homogenates of rat hearts was examined. Besides MAO only the NCR activity increased. However, both the total and the rotenone-insensitive NCR activities increased, with that of the rotenone-insensitive being about half of the total, which indicated that the effect of adrenalectomy was exerted on components of this enzyme localized on both the inner and outer membranes of the mitochondrion. The lack of effect on the other enzymes suggests that adrenalectomy has a relatively selective action on MAO and NCR, and does not work by a generalized increase in protein synthesis or by an effect on the FAD cofactor. The MAO increase was seen with a variety of substrates, and was due to a rise in Vmax without change in Km. The response to adrenalectomy in the summer differed from that seen in the winter. The possible reasons for these effects of adrenalectomy are discussed.
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PMID:The influence of adrenalectomy on monoamine oxidase and NADH cytochrome c reductase in the rat heart. 2 98

Cells of the Neurospora crassa slime mutant grown in sucrose medium exhibited low activities of glyoxysomal marker enzymes isocitrate lyase (ICL), malate synthetase (MS), and malate dehydrogenase. Transfer of the cells to a medium containing acetate as sole carbon source ("acetate medium") induced a strong increase in the activities of these enzymes in both the soluble and the crude particulate cell fraction. Soluble isocitrate lyase activity increased rapidly after a lag phase of about 45 minutes. Addition of 0.1 mM cycloheximide to the acetate medium 3 hours after transfer of the cells halted the rise of isocitrate lyase activity in either cell fraction, but the inhibition of the incorporation of ICL activity into the particulate cell fraction was delayed by 1 hour. Addition of 20 g/l glucose resulted in the immediate decrease of both soluble and particulate ICL activities. Transfer to acetate medium induced no change in the activities of other microbody marker enzymes such as catalase, uricase or D-amino acid oxidase. Resolution of crude homogenates of "slime" cells by sucrose density gradient centrifugation yielded two major protein bands: A mitochondrial band at a density of 1.180 kg/l showing maximum activites of fumarase, isocitrate dehydrogenase and cytochrome c oxidase, and a microbody-rich band which obviously consisted of two types of organelles with different biochemical properties. Maximum activities of ICL and MS sedimented at a density of 1.21 kg/l while the peaks of particulate uricase and catalase activities were recovered at 1.24 kg/l.
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PMID:Isolation and biochemical properties of two types of microbody from Neurospora crassa cells. 15 14

Measurement of argininosuccinase (I; EC 4.3.2.1) activity is useful in following the course of disease in hepatitis and in screening for the genetic defect, argininosuccinic aciduria. Methodology is proposed for a novel procedure for the determination of I in serum and erythrocytes. In the procedure, fumarate, generated in the reaction, is assayed by conversion to malate with fumarase, determining the malate enzymatically with malate dehydrogenase, and estimating the NADH formed spectrofluorometrically. By this procedure, the enzyme activity in serum from normal individuals is less than 11 mumol/liter of erthrocytes/per hour. The correlation coefficient between results by this method and by the colorimetric method, which measures the arginine generated in the reaction, is +0.97 for serum and +0.98 for erythrocytes. The proposed procedure has a relatively low initial blank, requires less serum, and is completed faster.
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PMID:Serum and erythocyte argininosuccinate lyase assay by NADH fluorescence generated from formed fumarate. 16 57

The activity of the enzymes of the citric acid cycle, glycolysis, and hexose monophosphate pathway was studied during germination of the spores of Bacillus anthracoides and upon their treatment with calcium hypochlorite. No activity of isocitrate dehydrogenase and glucose-6-phosphate dehydrogenase was found in the extracts of the vegetative cells, contrary to the spores and initiated spores. The activity of other enzymes changes but slightly in the course of germination of the spores. Treatment of the spores with calcium hypochlorite inhibited their initiation and germination and the activity of several enzymes, especially malate dehydrogenase, isocitrate dehydrogenase, and fumarase.
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PMID:[Change in the activity of the enzymatic systems of Bacillus anthracoides spores during germination and under the action of Ca hypochlorite]. 17 77

1. Oxalacetase from Asperigillus niger was found to be an inducible enzyme, the induction being dependent not only on neutralisation of the acidic growth medium but also on the presence of carbonate. An explanation is proposed. 2. Three methods were established for the quantitative determination of oxalacetase activity. These are based on the determination of the product acetate, on the absorbance of oxaloacetate and on coupling the hydrolysis of oxaloacetate to the oxidation of malate by NAD in the presence of malate dehydrogenase. 3. Oxalacetase was purified about 50-fold from cell-free extracts of A. niger and used to determine some of its properties such as kinetic constants. 4. 2S-[U-14C, 3-2H2] Malate in the presence of oxalacetase, NAD and malate dehydrogenase was partially converted to acetate and oxalate. The 3H/14C ratio of the isolated acetate was nearly twice as high as that of the malate used initially. The result demonstrates that the keto form of oxaloacetate, not the enol, is the substrate of the enzyme. 5. Equimolecular mixtures of 2S, 3S-[3-2H1] malate + 2S-[2-2H1] malate (mixture 1) and 2S, 3R-[3-2H1, 3H1] malate + 2S, 3R-[2-2H1, 3-3H1] malate (mixture 2) were prepared from 2S-[3-3H2] malate by incubation with fumarase in normal and tritiated water, respectively. The isolated mixture 1, in the presence of oxalacetase, NAD and malate dehydrogenase was incubated in tritiated water for formation of acetate and oxalate; the isolated mixture 2 was treated likewise in normal water. 6. The mixtures of symmetrically labelled [3H1] acetate and chiral acetates thus produced were isolated and the configuration of the [3H1, 3H1] acetate specimens was determined in the sequence acetate leads to malate leads to fumarate, as usual. The [2H1, 3H1] acetate derived from 2S, 3S-[3-2H1] malate (present in mixture 1( yielded a malate which on incubation with fumarase retained 65.0% of its total tritium content. This chiral acetate, therefore, had the R configuration. The [2H1, 3H1] acetate derived from 2S, 3R-[2-2H1, 3-3H1] malate produced a malate which retained 35% of its total tritium content, and therefore had the S configuration. 7. It was concluded that the detachment of the oxaloyl residue from oxaloacetate and its replacement by a proton proceed with inversion of configuration at the methylene group which becomes methyl during the hydrolysis.
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PMID:Partial purification and some properties of oxalacetase from Aspergillus niger. 17 20

The effect of various chloroactive compounds containing equal amounts of chlorine on respiration enzymes was studied in the spores of Bacillus anthracoides 96. These compounds inhibited the activity of malate dehydrogenase, fumarase, and aconitase but stimulated the activity of glucose-6-phosphate dehydrogenase, succinate dehydrogenase, and ketoglutarate dehydrogenase. Therefore, the action of these compounds is rather specific, and the inhibition of the activity of some enzymes is one of the factors causing the sporocidal effect.
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PMID:[Comparative effect of various chloroactive compounds on the enzyme systems of Bacillus anthracoides spores]. 18 61

A proposed mechanism [Clin. Chem. 19, 668 (1973)] for the inverse relationship between guanidinoacetate (I) and guanidinosuccinate (II) in human urine is explored. The mechanism proposes that canavaninosuccinate (III) may be reduced to form homoserine and II or, alternatively, that the III may be acted upon by a lyase to form canavanine and fumarate. The canavanine would then proceed to transamidinate to glycine to form I. This study demonstrates for the first time that lyase activity for converting III to canavanine and fumarate exists in human liver and kidney extracts. Transamidination from canavanine to glycine to form I is also readily accomplished with human tissue. Reductive cleavage of III to II and homoserine has been demonstrated before [Clin. Chem. 15, 397 (1969)]. The optimum pH for the lyase reaction is 6.5, for the reductive cleavage it is 8.7. In following the course of the lyase reaction, we developed a technique whereby the fumarate formed was hydrated with fumarase (EC 4.2.1.2) and then dehydrogenated with malate dehydrogenase (EC 1.1.1.37). The changes in absorbance of NADH formed in the reaction were then measured and used to determine the amount of fumarate formed, as a measure of lyase activity. Canavanino-succinate lyase activity follows pseudo-first-order reaction kinetics. The Michaelis constant of this lyase was 6.16 X 10-4 mol/liter, for argininosuccinate lyase 9.74 X 10-4 mol/liter. These data suggest that the binding affinity for III to the enzyme is greater than that for argininosuccinate. Glycine added to the reaction acts as an activator, probably because it removes the canavanine from the reaction mixture. On the other hand, arginine acts as an inhibitor of III-lyase. Other substances tested, such as canavanine, fumarate, and argininosuccinate had no effect on the reaction kinetics.
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PMID:Evidence supporting a proposed mechanism explaining the inverse relationship between guanidinoacetate and guanidinosuccinate in human urine. 23 5

A proposed mechanism [Clin. Chem. 19, 668 (1973)] for the inverse relationship beteen guanidinoacetate (I) and guanidinosuccinate (II) in human urine is explored. The mechanism proposes that canavaninosuccinate (III) may be reduced to form homoserine and II or, alternatively, that the III may be acted upon by a lyase to form canavine and fumarate. The canavanine would the proceed to transamidinate to glycine to form I. This study demonstrates for the first time that layse activity for converting III to canavanine and fumarate exists in human liver and kidney extracts. Transamidination from canavine to glycine to form I is also readily accomplised with human tissue. Reductive cleavage of III to II and homoserine has been demonstrated before [Clin. Chem. 15, 397 (1969)]. The optimum pH for the lyase reaction is 6.5, for the reductive cleavage it is 8.7. In follwing the course of the lyase reaction, we developed a technique whereby the fumarate formed was hydrated with fumarase (EC 4.2.1.2) and then dehydrogenated with malate dehydrogenase (EC. 1.1.1.37). The changes in absorbance of NADH formed in the reaction were then measured and used to determine the amount of fumarate formed, as a measure of lyase activity. Canavanino-succinate lyase activity follows pseudo-first-order reaction kinetics. The Michaelis constant of this lyase was 6.16 X 10-4 mol/liter, for argininosuccinate lyase 9.74 X 10.4 mol/liter. These data suggest that the binding afficinity for III to the enzyme is greater than that for argininosuccinate. Glycine added to the reaction acts as an activator, probably because is removes the canavanine from the reaction mixture. On the otherhand, arginine acts as an inhibitor of III-lyase. Other substances tested, such as canavaine, fumarate, and arginissuccinate had no effect on the reaction kinetics.
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PMID:Evidence supporting a proposed mechanism explaning the inverse relationship between guanidinoacetate and guanidinosuccinate in human urine. 23 6

Rat and calf adrenal cortex homogenates were found to contain three different malic enzymes. Two were strictly NADP+-dependent and were localized, one each, in the cytosol and the mitochondrial fractions, respectively. These two enzymes appear to be identical to those described by Simpson and Estabrook (Simpson, E. R., and Estabrook, R. W. (1969) Arch. Biochem. Biophys. 129, 384-395). The third was NAD(P)+-linked and was present in the mitochondrial fraction only. All three malic enzymes separated as distinct bands during electrophoresis on 5 percent polyacrylamide slab gels at pH 9.0. Marker enzymes and the mitochondrial malic enzymes migrated together in intact mitochondria during sucrose density gradient centrifugations despite changes in the equilibrium position of the mitochondria promoted by energy-dependent calcium phosphate accumulation. In adrenal cortex mitochondria subfractionated by the method of Sottocasa et al. (SOTTOCASA, G.L., KUYLENSTIERNA, B., ERNSTER, L., and BERGSTAND, A. (1967) J. Cell Biol. 32, 415-438), both malic enzymes were associated with the inner membrane-matrix space. Sonication solubilized the two malic enzymes along with the matrix space marker enzymes. The NAD(P)+-dependent malic enzyme was purified 100-fold from calf adrenal cortex mitochondria. The final preparation was free of malic dehydrogenase, fumarase, the strictly NADP+-linked malic enzyme and adenylate kinase. Either Mn24 orMg2+ was required for activity and 1 mol of pyruvate was formed for each mole of NAD+ and NADP+ reduced. The pH optima with NAD+ and NADP+ were 6.5 tp 7.0 and 6.0 to 6.5, respectively. Michaelis-Menten kinetics were observed on the alkaline side. Fumarate, succinate, and isocitrate were positive and ATP and ADP were negative modulators of the regulatory enzyme. The modulators did not influence the stoichiometry and they were not metabolized during the reaction. Under Vmax conditions the ratios for the rate of NAD+:NADP+ reduction were 1.76 and 1.15 at pH 7.4 and 6.0, respectively. The apparent Michaelis constants also differed depending on the pH and the coenzyme. At pH 7.4 (in the presence of 5 mM fumarate) and at pH 6.0 (no fumarate) the Km values for (-)-malate, NAD+, and Mn2+ were 1.7, 0.16, and 0.15 mM, and 0.31, 0.06, and 0.09 mM, respectively. At pH 7.4 (5MM fumarate) and pH 6.0 (no fumarate), the Km values for (-)-malate, NADP+, and Mn2+ were 6.5, 0.62, and 0.59 mM, and 0.68. 0.12, and 0.31 mM, respectively. The apparent Ki values for ATP with NAD+ and NADP+ as coenzyme were 0.42 and 0.27 mM, respectively.
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PMID:The mitochondrial malic enzymes. I. Submitochondrial localization and purification and properties of the NAD(P)+-dependent enzyme from adrenal cortex. 23 89

The regulation of alpha-ketogluterate dehydrogenase, succinate dehydrogenase, fumarase, malate dehydrogenase, and malic enzyme has been studied in Bacillus subitilis. The levels of these enzymes increase rapidly during late exponential phase in a complex medium and are maximal 1 to 2 h after the onset of sporulation. Regulation of enzyme synthesis has been studied in the wild type and different citric acid cycle mutants by adding various metabolites to the growth medium. Alpha-ketoglutarate dehydrogenase is induced by glutamate or alpha-ketoglutarate; succinate dehydrogenase is repressed by malate; and fumarase and malic enzyme are induced by fumarate and malate, respectively. The addition of glucose leads to repression of the citric acid cycle enzymes whereas the level of malic enzyme is unaffected. Studies on the control of enzyme activities in vitro have shown that alpha-ketoglutarate dehydrogenase and succinate dehydrogenase are inhibited by oxalacetate. Enzyme activities are also influenced by the energy level, expressed as the energy charge of the adenylate pool. Isocitrate dehydrogenase, alpha-ketoglutarate dehydrogenase, succinate dehydrogenase, and malic enzyme are inhibited at high energy charge values, whereas malate dehydrogenase is inhibited at low energy charge. A survey of the regulation of the citric acid cycle in B.subtilis, based on the present work and previously reported results, is presented and discussed.
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PMID:Regulation of the dicarboxylic acid part of the citric acid cycle in Bacillus subtilis. 80 68


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