Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:4.1.2.13 (aldolase)
3,461 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

At a concentration of 2.5 mM, dl-glyceraldehyde 3-phosphate has a bactericidal effect upon Escherichia coli. The glycerol 3-phosphate transport system is required for the entry of the biologically active l-enantiomer. l-Glyceraldehyde must be phosphorylated by the cell to exert its full effect upon growth. The addition of dl-glyceraldehyde 3-phosphate to a culture of E. coli caused no preferential inhibition of the accumulation of deoxyribonucleic acid, ribonucleic acid, or phosphoglycerides, although protein accumulation was less affected. Studies with mutant strains ruled out catabolic glycerol 3-phosphate dehydrogenase, anabolic nicotinamide adenine dinucleotide (phosphate):sn-glycerol 3-phosphate oxidoreductase, and fructose 1,6-diphosphate aldolase as the primary sites of action. l-Glyceraldehyde 3-phosphate is a competitive inhibitor of sn-glycerol 3-phosphate in the reactions catalyzed by acyl coenzyme A:sn-glycerol 3-phosphate acyltransferase (K(i) of 1.8 mM) and cytidine 5'-diphosphate-diglyceride:sn-glycerol 3-phosphate phosphatidyltransferase (K(i) of 2.7 mM). A K(m) mutant for the former enzyme was susceptible to the inhibitor. l-Glyceraldehyde 3-phosphate does not affect acyl coenzyme A:lysophosphatidate acyltransferase activity. In vivo, phosphatidylethanolamine and phosphatidylglycerol accumulation are inhibited to the same extent by the addition of dl-glyceraldehyde 3-phosphate to a culture of E. coli.
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PMID:L-Glyceraldehude 3-phosphate, a bactericidal agent. 31 47

Wild-type strains of Escherichia coli are unable to use L-1,2-propanediol as a carbon and energy source. A series of mutants, able to grow on this compound at progressively faster rates, had been isolated by repeated transfers to a medium containing 20 mM L-1,2-propanediol. These strains synthesize at high constitutive levels a propanediolmicotinamide adenine dinucleotide oxidoreductase, an enzyme serving as a lactaldehyde during L-fucose fermentation by wild type cells. In this study, a mutant that can grow rapidly on the novel carbon source was subjected to further selection in a medium containing L-1,2-propanediol never exceeding 0.5 mM to obtain a derivative that has an increased power to extract the substrate from the medium. The emerging mutant exhibited four changes at the enzymatic level: (i) fuculose 1-phosphate aldolase activity is lost; (ii) the constitutive propanediol oxidoreductase activity is increased in its level; (iii) lactaldehyde dehydrogenase becomes constitutive and shows an elevated specific activity in crude extracts; and (iv) at low concentrations of propanediol, the facilitated diffusion across the cell membrane is enhanced. Changes two to four seem to act in concert in the trapping of propanediol by hastening its rate of entry and conversion to an ionized metabolite, lactate.
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PMID:Evolution of propanediol utilization in Escherichia coli: mutant with improved substrate-scavenging power. 36 12

Wild-type strains of Escherichia coli are unable to use L-1,2-propanediol as a carbon and energy source. Strain 3, a mutant selected for the ability to grow on this compound at progressively more rapid rates, synthesizes constitutively a nicotinamide adenine dinucleotide-linked propanediol oxidoreductase. This enzyme is normally synthesized during anaerobic growth on L-fucose when it functions as a lactaldehyde reductase. Propanediol, the end product of this fermentation process, escapes irretrievably into the medium. The propanediol-utilizing mutant can no longer grow on fucose in either the presence or absence of molecular oxygen. In the present study nine independent lines of propanediol-positive mutants were characterized. One mutant, strain 418, attained a propanediol growth rate close to that of strain 3 without loss of the ability to grow on fucose. In all cases examined, however, prolonged selection on propanediol did result in the emergence of fucose-negative mutants. All of these mutants had enzyme patterns similar to that of strain 3; namely, fucose permease, fucose isomerase, and fuculose kinase were noninducible, whereas fuculose 1-phosphate aldolase was constitutive. In strain 418 and in the fucose-positive predecessors of the other mutants, the first four enzymes in the pathway remained inducible, as in the wild-type strain. Improvements in the growth rate on propanediol appeared to reflect principally the increased activity level of the oxidoreductase during the early stages of evolution. According to transductional analysis, the mutations affecting the ability to grow on propanediol and those that affect the expression of the first enzymes in the fucose pathway were very closely linked. The loss of the ability to grow on fucose is thought to be a mechanistic consequence incidental to the remodeling of the regulatory system in favor of the utilization of the novel carbon source.
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PMID:Regulatory changes in the fucose system associated with the evolution of a catabolic pathway for propanediol in Escherichia coli. 40 Jul 96

Detailed histochemical studies have been conducted on the distribution of various enzymes, including thiamine pyrophosphatase, alpha-glucan phosphorylase, hexokinase, glucose-6-phosphate dehydrogenase, aldolase, glycerol-3-phosphate dehydrogenase; menadion oxidoreductase, lactate dehydrogenase and succinate dehydrogenase in various components of the cerebellum of healthy adult male rats of the Wistar strain. The thiamine pyrophosphatase reaction showed the morphological patterns of the GOLGI apparatus characteristic for each kind of cells. The GOLGI apparatus is a simple network in stellate cells, but it can be classified into the same 5 categories in basket cells and GOLGI type II cells. The GOLGI apparatus in the latter 2 cell types appears to undergo cyclic changes. A few GOLGI type II cells have a supranuclear form (Type II) and some cells show disintegration and "budding-off" of the GOLGI apparatus. The GOLGI apparatus in PURKINJE cells can be classified into 4 categories including a perinuclear strand form (Type III), but most of them show randomly distributed granules and vesicles. Lightly stained networks are observable in astrocytes and oligodendrocytes. They do not show polarity in astrocytes whereas they have extensions in a few oligodendrocytes. BERGMANN glia may undergo cyclic changes indicating more advance differentiation than astrocytes and oligodendrocytes. Cerebellar glomerula show lightly stained networks with many fine granules. Granule cells, stellate cells, and basket cells are all poorly equipped equally with the EMBDEN-MEYERHOF (EM) pathway and with the hexosemonophosphate (HMP) shunt. GOLGI type II cells are richly equipped almost equally with both the EM pathway and the HMP shunt. All these neurons probably derive energy mainly from glucose in the circulating blood. PURKINJE cells may belong to the category of "usual neurons", because they are moderately equipped both with the EM pathway and the HMP shunt. However, they may derive their energy from the BERGMANN glia which have intense hexokinase activity but weak succinate dehydrogenase activity. The BERGMANN glia are more richly equipped with the HMP shunt than with the EM pathway and are rich in lactate dehydrogenase suggesting an "exceptional metabolic pattern". These glia may have active synthesizing ability. Astrocytes and oligodendrocytes are equipped with all the enzymes tested, and they show a tendency to surround the glomeruli. It is suggested that the glomerula may be surrounded by the glial sheaths with strong hexokinase activity, and that they may contain alpha-glucan phosphorylase, glucose-6-phosphate dehydrogenase, and glycerol-3-phosphate dehydrogenase in addition to the succinate dehydrogenase already reported. A few PURKINJE cells showed perinuclear concentrations of the reaction product only of succinate dehydrogenase at the sites of contacts between nucleoli and nuclear membranes. It is suggested that the nucleolus may receive adenosine at the sites of contacts between nucleoli and nuclear membranes...
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PMID:Histochemical studies on the morphology of the Golgi apparatus and on the distribution of some enzymes concerned with carbodydrate metabolism in the rat cerebellum. 40 26

L-1,2-Propanediol is an irretrievable end product of L-fucose fermentation by Escherichia coli. Selection for increased aerobic growth rate on propanediol results in the escalation of basal synthesis of the NAD+-linked oxidoreductase encoded by fucO, a member of the fuc regulon for the utilization of L-fucose. In general, when fucO becomes constitutively expressed, two other simultaneous changes occur: the fucA gene encoding fuculose-1-phosphate aldolase becomes constitutively expressed and the fucPIK operon encoding fucose permease, fucose isomerase, and fuculose kinase becomes noninducible. In the present study, we show that fucO and fucA form an operon which is divergently transcribed from the adjacent fucPIK operon. In propanediol-positive and fucose-negative mutants the cis-controlling region shared by the operons fucAO and fucPIK is lengthened by 1.2 kilobases. DNA hybridization identified the insertion element to be IS5. This element, always oriented in the same direction with the left end (the BglII end) proximal to fucA, apparently causes constitutive expression of fucAO and noninducibility of fucPIK. The DNA of the fucAO operon and a part of the adjacent fucP was sequenced.
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PMID:Constitutive activation of the fucAO operon and silencing of the divergently transcribed fucPIK operon by an IS5 element in Escherichia coli mutants selected for growth on L-1,2-propanediol. 255 71

L-Fucose is used by Escherichia coli through an inducible pathway mediated by a fucP-encoded permease, a fucI-encoded isomerase, a fucK-encoded kinase, and a fucA-encoded aldolase. The adolase catalyzes the formation of dihydroxyacetone phosphate and L-lactaldehyde. Anaerobically, lactaldehyde is converted by a fucO-encoded oxidoreductase to L-1,2-propanediol, which is excreted. The fuc genes belong to a regulon comprising four linked operons: fucO, fucA, fucPIK, and fucR. The positive regulator encoded by fucR responds to fuculose 1-phosphate as the effector. Mutants serially selected for aerobic growth on propanediol became constitutive in fucO and fucA [fucO(Con) fucA(Con)], but noninducible in fucPIK [fucPIK(Non)]. An external suppressor mutation that restored growth on fucose caused constitutive expression of fucPIK. Results from this study indicate that this suppressor mutation occurred in crp, which encodes the cyclic AMP-binding (or receptor) protein. When the suppressor allele (crp-201) was transduced into wild-type strains, the recipient became fucose negative and fucose sensitive (with glycerol as the carbon and energy source) because of impaired expression of fucA. The fucPIK operon became hyperinducible. The growth rate on maltose was significantly reduced, but growth on L-rhamnose, D-galactose, L-arabinose, glycerol, or glycerol 3-phosphate was close to normal. Lysogenization of fuc+ crp-201 cells by a lambda bacteriophage bearing crp+ restored normal growth ability on fucose. In contrast, lysogenization of [fucO(Con)fucA(Con)fucPIK(Non)crp-201] cells by the same phage retarded their growth on fucose.
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PMID:A mutant crp allele that differentially activates the operons of the fuc regulon in Escherichia coli. 283 41

Dissimilation of L-fucose as a carbon and energy source by Escherichia coli involves a permease, an isomerase, a kinase, and an aldolase encoded by the fuc regulon at minute 60.2. Utilization of L-rhamnose involves a similar set of proteins encoded by the rha operon at minute 87.7. Both pathways lead to the formation of L-lactaldehyde and dihydroxyacetone phosphate. A common NAD-linked oxidoreductase encoded by fucO serves to reduce L-lactaldehyde to L-1,2-propanediol under anaerobic growth conditions, irrespective of whether the aldehyde is derived from fucose or rhamnose. In this study it was shown that anaerobic growth on rhamnose induces expression of not only the fucO gene but also the entire fuc regulon. Rhamnose is unable to induce the fuc genes in mutants defective in rhaA (encoding L-rhamnose isomerase), rhaB (encoding L-rhamnulose kinase), rhaD (encoding L-rhamnulose 1-phosphate aldolase), rhaR (encoding the positive regulator for the rha structural genes), or fucR (encoding the positive for the fuc regulon). Thus, cross-induction of the L-fucose enzymes by rhamnose requires formation of L-lactaldehyde; either the aldehyde itself or the L-fuculose 1-phosphate (known to be an effector) formed from it then interacts with the fucR-encoded protein to induce the fuc regulon.
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PMID:Cross-induction of the L-fucose system by L-rhamnose in Escherichia coli. 330 11

A detailed study of the glucose fermentation pathway and the modulation of catabolic oxidoreductase activities by energy sources (i.e., glucose versus lactate or fumarate) in Propionispira arboris was performed. 14C radiotracer data show the CO2 produced from pyruvate oxidation comes exclusively from the C-3 and C-4 positions of glucose. Significant specific activities of glyceraldehyde-3-phosphate dehydrogenase and fructose-1,6-bisphosphate aldolase were detected, which substantiates the utilization of the Embden-Meyerhoff-Parnas path for glucose metabolism. The methylmalonyl coenzyme A pathway for pyruvate reduction to propionate was established by detection of significant activities (greater than 16 nmol/min per mg of protein) of methylmalonyl coenzyme A transcarboxylase, malate dehydrogenase, and fumarate reductase in cell-free extracts and by 13C nuclear magnetic resonance spectroscopic demonstration of randomization of label from [2-13C]pyruvate into positions 2 and 3 of propionate. The specific activity of pyruvate-ferredoxin oxidoreductase, malate dehydrogenase, fumarate reductase, and transcarboxylase varied significantly in cells grown on different energy sources. D-Lactate dehydrogenase (non-NADH linked) was present in cells of P. arboris grown on lactate but not in cells grown on glucose or fumarate. These results indicate that growth substrates regulate synthesis of enzymes specific for the methylmalonyl coenzyme A path and initial substrate transformation.
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PMID:Regulation of carbon and electron flow in Propionispira arboris: relationship of catabolic enzyme levels to carbon substrates fermented during propionate formation via the methylmalonyl coenzyme A pathway. 341 Aug 21

The enzyme pattern of Saccharomyces cerevisiae was followed during batch growth and in continuous culture in a synthetic medium limited for glucose under aerobic conditions. Seven enzymes were measured: succinate-cytochrome c oxidoreductase, malate dehydrogenase, nicotinamide adenine dinucleotide-linked glutamate dehydrogenase, malate synthase, isocitrate lyase, aldolase, and nicotinamide adenine dinucleotide phosphate (NADP(+))-linked glutamate dehydrogenase. During fermentation of glucose and high growth rate (mu) during the first log phase in batch experiments, the first five enzymes (group I) were repressed, and aldolase and NADP(+)-linked glutamate dehydrogenase (group II) were derepressed. During growth on the accumulated ethyl alcohol and lower mu, the group I enzymes were preferentially formed and the other two were repressed. A sequence of derepression of the group I enzymes was found during the shift from glucose to ethyl alcohol metabolism, which can be correlated with a strong increase in the percentage of single (nonbudding) cells in the population. A correlation between the state of cells in the budding cycle and enzyme repression and derepression is suggested. In continuous culture, the enzyme pattern was shown to be related to the growth rate. The group I enzymes were repressed at high growth rates, while the group II enzymes were derepressed. Each enzyme exhibits a different dependence. The enzyme pattern is shown to depend on the rate of substrate consumption as well as on the type of metabolism and to be correlated with the budding cycle. The enzyme pattern is considered to be controlled by changes of intracellular catabolic or metabolic conditions inherent in the division cycle.
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PMID:Enzyme pattern and aerobic growth of Saccharomyces cerevisiae under various degrees of glucose limitation. 438 90

Cells of the aerotolerant anaerobe Giardia lamblia respire in the presence of oxygen. Endogenous respiration is stimulated by glucose but not by other carbohydrates and Krebs cycle intermediates. Endogenous and glucose-stimulated respiration are insensitive to cyanide, malonate, and 2,4-dinitrophenol, but are inhibited by atabrin and iodoacetamide. G. lamblia produces ethanol, acetate and CO2 both aerobically and anaerobically either from endogenous reserves or exogenous glucose. Molecular hydrogen is not produced. The following enzyme activities were detected in homogenates: hexokinase, fructose-biphosphate aldolase, pyruvate kinase, phosphoenolpyruvate carboxykinase, malate dehydrogenase, malate dehydrogenase (decarboxylating), pyruvate synthase, acetyl-CoA synthetase, alcohol dehydrogenase (NADP+), NADH dehydrogenase, NADPH dehydrogenase, NADPH oxidoreductase and superoxide dismutase. The enzymes of energy and carbohydrate metabolism are nonsedimentable (109 000 x g for 30 min). Activities of lactate dehydrogenase, hydrogenase, phosphate acetyltransferase, acetate kinase, citrate synthase, succinate dehydrogenase, fumarate hydratase and catalase were below the limits of detection. The results suggest the occurrence of glycolysis, energy production by substrate level phosphorylation and a flavin, iron-sulfur protein mediated electron transport system as well as the absence of cytochrome mediated oxidative phosphorylation and functional Krebs cycle.
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PMID:Energy metabolism of the anaerobic protozoon Giardia lamblia. 610 7


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