Serine transhydroxymethylase: mechanism of aldolase activation by folate.
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Animals↗
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Results for “Fructose-Bisphosphate Aldolase”
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Quantitative cytochemical measurement of glyceraldehyde 3-phosphate dehydrogenase activity.
A system has been developed for the quantitative measurment of glyceraldehyde 3-phosphate dehydrogenase activity in tissue sections. An obstacle to the histochemical study of this enzyme has been the fact that the substrate, gylceraldehyde 3-phosphate, is very unstable. In the present system a stable compound, fructose 1, 6-diphosphate, is used as the primary substrate and the demonsatration of the glyceraldehyde 3-phosphate dehydrogenase activity depends on the conversion of this compound into the specific substrate by the aldolase present in the tissue. The characteristics of the dehydrogenase activity resulting from the addition of fructose 1, 6-diphosphate, resemble closely the known properties of purified glyceraldehyde 3-phosphate dehydrogenase. Use of polyvinyl alcohol in the reaction medium prevents release of enzymes from the sections, as occurs in aqueous media. Although in this study intrinsic aldolase activity was found to be adequate for the rapid conversion of fructose 1, 6-diphosphate into the specific substrate for the dehydrogenase, the use of exogenous aldolase may be of particular advantage in assessing the intergrity of the Embden-Meyerhof pathway.
Animals↗
Affinity labeling of a previously undetected essential lysyl residue in class I fructose bisphosphate aldolase.
The affinity label N-bromoacetylethanolamine phosphate (BrAcNHEtOP) has been used previously at pH 6.5 to identify His-359 of rabbit muscle aldolase as an active site residue. We now find that the specificity of the reagent is pH-dependent. At pH 8.5, alkylation with 14C-labeled BrAcNHEtOP abolishes both fructose-1,6-P2 cleavage activity and transaldolase activity. The stoichiometry of incorporation, the kinetics of inactivation, and the protection against inactivation afforded by a competitive inhibitor or dihydroxyacetone phosphate are consistent with the involvement of an active site residue. A comparison of 14C profiles obtained from chromatography on the amino acid analyzer of acid hydrolysates of inactivated and protected samples reveals that inactivation results from the alkylation of lysyl residues. The major peptide in tryptic digests of the inactivated enzyme has been isolated. Based on its amino acid composition and the known sequence of aldolase, Lys-146 is the residue preferentially alkylated by the reagent. Aldolase modified at His-359 is still subject to alkylation of lysine; thus Lys-146 and His-359 are not mutually exclusive sites. However, aldolase modified at Lys-146 is not subject to alkylation of histidine. One explanation of these observations is that modification of Lys-146 abolishes the binding capacity of aldolase for substrates and substrate analogs (BrAcNHEtOP), whereas modification of his-359 does not. Consistent with this explanation is the ability of aldolase modified at His-359 to form a Schiff base with substrate and the inability of aldolase modified at Lys-146 to do so. Therefore, Lys-146 could be one of the cationic groups that functions in electrostatic binding of the substrate's phosphate groups.
Affinity Labels↗
Fructose 1,6-diphosphate aldolase from rabbit muscle. Effect of pH on the rate of formation and on the equilibrium concentration of the carbanion intermediate.
The rate of oxidation of ferricyanide of the aldolase-dihydroxyacetone phosphate complex was measured under different conditions. The following conclusions are drawn. 1. In the cleavage of fructose diphosphate, catalysed by native aldolase, the steady-state concentration of the enzyme-dihydroxyacetone phosphate carbanion intermediate represents less than 6% of the total enzyme-substrate intermediates. 2. Fructose diphosphate and dihydroxyacetone phosphate compete for the four catalytic sites on aldolase, the binding of fructose diphosphate being about twice as tight. 3. The equilibrium concentration of the carbanion intermediate formed by reaction of carboxypeptidase-treated aldolase with dihydroxyacetone phosphate is independent of pH between 5.0 and 9.0. The rates of fromation of the carbanion intermediate and of the reverse reaction are, however, concomitantly increased by increasing pH between 5.0 and 6.5.
Animals↗
Biochemical and biophysical changes in guinea pigs after acute head injury.
Animal experiments were set up mainly to derive additional diagnostic data from the study of biochemical changes after acute head injury. In standardized experiments guinea pigs were subjected in groups of 20 to three identical head injuries, each of either 1.0 J or 1.5 J intensity. The trauma was likely to result in a concussion or contusion syndrome similar to that found in man; 40 animals served as controls. During the 60 min after injury observation and measurement of body functions did not reveal signs of a shock-like condition or hypoxaemia in the traumatized animals compared with control animals. Superficial anaesthesia probably did not influence the findings. Temperature and respiration were altered significantly in all the animals receiving head injuries. Blood gas analysis showed a decrease of standard bicarbonate only after the 1.5 J injury but even though hypoxaemia was not present 2,3-diphosphoglycerate values and P50 increased, compared with the control animals. The fall of plasma lipid concentrations reported probably had to be seen as a sympathomimetic effect of the minor (1.0 J) trauma. Of special significance was the increased activity of malate dehydrogenase and aldolase, found only in the blood of severely traumatized animals, as this could serve as an early diagnostic aid for evaluating head injuries.
Alanine Transaminase↗
Histochemical observations on the occurrence of glycolytic and pentose phosphate cycle enzymes in the hepatopancreas and their possible relation to eyestalk factor(s) in the crab Scylla serrata (Forskal).
Histochemical studies were carried out on some of the glycolytic enzymes viz. phosphorylase, aldose, alpha-glycerophosphate dehydrogenase (alpha-GPDH) and lactic dehydrogenase (LDH) and a key enzyme of the pentose phosphatase cycle, glucose-6-phosphate dehydrogenase (G-6-PDH), in the hepatopancreas of Scylla serrata (Forskal). 1. Weak activities of phosphorylase and aldolase and strong-activities of alpha-GPDH and LDH were noticed mainly in the brush border of the tubules and R-cell cytoplasm. A trace activity of G-6-PDH was noticed in the brush border. 2. Bilateral eyestalk removal results in inhibition of both phosphorylase and aldolase. However, enhanced activities of alpha-GPDH and LDH were noticeable 4 h after the operation. The G-6-PDH activity remained unaltered till 24 h. 3. Injection of eyestalk extract into both intact and destalked crabs activated all the enzymes.
Animals↗
Fructose 1,6-bisphosphate aldolase activity of Rhizobium species.
FDP aldolase was found to be present in the cell-free extracts of Rhizobium leguminosarum, Rhizobium phaseoli, Rhizobium trifolii, Rhizobium meliloti, Rhizobium lupini, Rhizobium japonicum and Rhizobium species from Arachis hypogaea and Sesbania cannabina. The enzyme in 3 representative species has optimal activity at pH 8.4 in 0.2M veronal buffer. The enzyme activity was completely lost by treatment at 60 degrees C for 15 min. The Km values were in the range from 2.38 to 4.55 X 10(-6)M FDP. Metal chelating agents inhibited enzyme activity, but monovalent or bivalent metal ions failed to stimulate the activity. Bivalent metal ions in general were rather inhibitory.
Cell-Free System↗
Equilibrium studies on the refolding and reactivation of rabbit-muscle aldolase after acid dissociation.
Dissociation, denaturation, and deactivation of aldolase from rabbit muscle in the acid pH range have been investigated using sedimentation analysis, fluorescence, circular dichroism, and activity tests. Under comparable experimental conditions the pH-dependent profiles of deactivation and denaturation parallel the dissociation of the enzyme. In the range of dissociation at pH4-5tetramers and monomers are in equilibrium. Intrinsic chromophores and far-ultraviolet circular dichroism suggest the transition to be a complex multistep process. At pH approximately 2.3 the enzyme is split into its fully inactive monomers which still contain some residual secondary structure. After reassociation under optimum conditions (0.2 M phosphate buffer pH 7.6, 1 mM EDTA, 0.1 mM dithiothreitol, 0 degrees C, enzyme concentration 0.4-59 mug/ml) up to 95% enzymic activity is recovered which belongs to a renatured tetrameric species indistinguishable from the native enzyme by all available biochemical and physicochemical criteria.
Animals↗
Mycobacterium tuberculosis MEM39 (Rv1977) hijacks host aldolase A (ALDOA) to subvert immunometabolism to facilitate bacterial intracellular survival.
Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis (TB), is the leading cause of infectious disease-related death. As a major intracellular pathogen, Mtb can escape clearance by the immune system, but the underlying molecular mechanisms remain incompletely elucidated. Specific genomic regions of deletion (RD)-encoded proteins in virulent Mtb H37Rv have been implicated in modulating pathogenicity and immunity. Here, we report a novel RD15-encoding protein, Rv1977 (a mycobacterial cell wall protein with a size of 39 kDa, named MEM39), which facilitates Mtb survival in macrophages. The survival of the Mtb H37Rv MEM39-deficient strain is reduced in both macrophage and murine infection models. Furthermore, the mycobacterial MEM39 protein binds fructose-diphosphate aldolase A (ALDOA), a key enzyme of glycolysis, thereby impairing ALDOA enzyme activity, disrupting macrophage metabolite flux, and reducing lactate production. The MEM39-ALDOA interaction also suppresses lysosomal acidification; reduces NLRP3 inflammasome activation and the production of proinflammatory cytokines (TNF-α, IL-6 and IL-1β); and thereby promotes bacterial survival within macrophages. Disruption of the interaction between MEM39-ALDOA and a cell-penetrating synthetic peptide (VLARYASICQ) significantly suppressed Mtb survival by restoring lactate production, lysosome acidification and proinflammatory cytokine production in both macrophage and mouse infection models. These findings revealed that mycobacterial MEM39 negatively regulates host immune defense through reprogramming ALDOA-mediated glycolysis in macrophages, thereby forming a "mycobacterial MEM39 virulence factor-glycolysis metabolism-immunity" regulatory axis. Targeting MEM39 or the MEM39-ALDOA interaction interface holds promise as a new therapeutic strategy against tuberculosis.
Mycobacterium tuberculosis↗
[Carbohydrate and pyruvic acid degradation pathways in Fusidium coccineum strains with varying levels of antibiotic synthesis].
A number of enzymes and reactions of glycolysis, pentose-phosphate cycle and degradation of pyruvic acid in strains of F. coccineum with various levels of antibiotic production was studied comparatively. The experiments showed that highly productive strains were characterized by higher activity of the NADP-deficient enzymes of the pentoze-phosphate cycle as compared to the low active strains. The activity levels of glycolytic enzymes, such as fructose-diphosphate-aldolase and 3-phosphoglycerolaldehydehydrogenase did not practically differ. Significant differences were found in the reactions of puryvic acid degradation: the activity of cytoplasmic pyruvatedecarboxylase in the mutant with high antibiotic production level was lower than that in the low productive strain, while oxidation of the pyruvate of the mitochondrial fraction was on the contrary more intensive than in the highly productive strain. Therefore, metabilism in the strains studied was characterized by ever-increasing biochemical changes with an increase in their antibiotic productivity. Lowering of the growth rate of the mutants as their capacity for antibiotic supersynthesis increased and subsequently the anabolic processes became more intensive was accompanied by increasing derepression of the key enzymes of carbohydrate metabolism and in particular NADR-deficient dehydrogenase of the pentose cycle and pyruvatedehydrogenase, significant for fusidin biosynthesis and providing production of the antibiotic of steroid nature by cofactor NADP-H and acetyl-KoA, the primary precursor.
Anti-Bacterial Agents↗
ALDOC and PGK1 coordinately induce glucose metabolism reprogramming and promote development of colorectal cancer.
Colorectal cancer (CRC) remains a significant health challenge globally, demanding a comprehensive understanding of its molecular underpinnings for effective management. In this study, we investigated the role of Aldolase C (ALDOC), a glycolytic enzyme, in CRC pathogenesis. Transcriptomic analysis of CRC tissues from The Cancer Genome Atlas (TCGA) revealed a substantial upregulation of ALDOC, correlating with adverse clinical outcomes. Immunohistochemical (IHC) staining of locally collected patient-derived tissues corroborated these findings, demonstrating elevated ALDOC expression in tumor tissues, particularly in advanced stages. Functional studies elucidated the regulatory role of ALDOC in CRC cell phenotypes. ALDOC knockdown significantly inhibited cell proliferation, induced apoptosis, arrested cell cycle progression, and suppressed cell migration in vitro. Moreover, in vivo studies using xenograft models confirmed that ALDOC knockdown attenuated tumor growth. Mechanistically, ALDOC was found to interact with hypoxia-inducible factor 1 alpha (HIF1A) and enhance its transcriptional activity on phosphoglycerate kinase 1 (PGK1), a key glycolytic enzyme. Dual-luciferase reporter assays and chromatin immunoprecipitation experiments validated the ALDOC-mediated transcriptional activation of PGK1. Further functional rescue experiments revealed a synergistic interplay between ALDOC and PGK1 in regulating CRC cell phenotypes. Additionally, ALDOC was implicated in promoting aerobic glycolysis in CRC cells, potentially through PGK1 regulation. Collectively, our findings unveil ALDOC as a critical regulator of CRC pathogenesis, offering insights into its potential as a therapeutic target and highlighting the ALDOC/PGK1 axis as a promising avenue for further investigation in CRC.
Humans↗
Epitranscriptomic Regulation of ALDOA by SHMT2-Mediated m6A Modification Drives Gastric Cancer Malignancy.
Gastric cancer (GC) remains a leading cause of cancer-related mortality worldwide, with limited therapeutic advancements despite progress in early detection. Serine hydroxymethyltransferase 2 (SHMT2), a key metabolic enzyme, and fructose-1,6-bisphosphate aldolase A (ALDOA), a glycolytic enzyme, are implicated in tumor progression. However, the molecular mechanisms linking SHMT2 and ALDOA in GC remain unclear. This study investigates how SHMT2 regulates ALDOA expression via m6A RNA modification to drive GC malignancy. Bioinformatic analyses (TCGA, LinkedOmics, and SRAMP) were used to assess SHMT2 expression in GC patients and identify its correlated genes. In vitro experiments (CCK-8, EdU, Transwell, and wound healing) evaluated the effects of SHMT2 overexpression or knockdown on GC cell proliferation, migration, invasion, and glycolysis. m6A modification of ALDOA was analyzed via MeRIP-PCR and dual-luciferase assays, while RNA stability was assessed using actinomycin D treatment. Xenograft models validated SHMT2's role in vivo. SHMT2 was upregulated in GC tissues and cell lines, correlating with advanced tumor stages and poor prognosis. SHMT2 knockdown suppressed GC cell viability, migration, invasion, and glycolysis, while overexpression enhanced these traits. Mechanistically, SHMT2 increased S-adenosylmethionine levels, promoting ALDOA m6A modification, likely mediated through the predicted site 1 (position 291). This modification stabilized ALDOA mRNA via IGF2BP1 recognition, an m6A reader. ALDOA overexpression reversed the tumor-suppressive effects of SHMT2 knockdown. In vivo, SHMT2 depletion reduced tumor growth and Ki67 expression in xenograft models. In conclusion, SHMT2 drives GC progression by enhancing ALDOA expression through m6A modification and IGF2BP1-mediated stabilization. Targeting the SHMT2-ALDOA axis represents a promising therapeutic strategy for gastric cancer.
Humans↗
Fructose-1-phosphate-6-sulfate as an alternative substrate for aldolase and fructose-1,6-diphosphatase.
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Animals↗
Phosphonomethyl analogues of hexose phosphates.
The analogue of fructose 1,6-bisphosphate in which the phosphate group, -O-PO3H2, on C-6 is replaced by the phosphonomethyl group, -CH2-PO3H2, was made enzymically from the corresponding analogue of 3-phosphoglycerate. It was a substrate for aldolase, which was used to form it, but not for fructose 1,6-bisphosphatase. It was hydrolysed chemically to yield the corresponding analogue of fructose 6-phosphate [i.e. 6-deoxy-6-(phosphonomethyl)-D-fructose, or, more strictly, 6,7-dideoxy-7-phosphono-D-arabino-2-heptulose]. This proved to be a substrate for the sequential actions of glucose 6-phosphate isomerase, glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase. Thus seven out of the nine enzymes of the glycolytic and pentose phosphate pathways so far tested catalyse the reactions of the phosphonomethyl isosteres of their substrates.
Fructose-Bisphosphatase↗
[On the enzymatics of the microbial breakdown of pyrazone (author's transl)].
From samples of earth taken in different parts of the world bacteria were isolated which grow on pyrazone as the only source of carbon. When these bacteria are grown in a pyrazone mineral salt medium, four compounds are excreted into the medium. The structures of these compounds furnish information on the catabolic route of pyrazone. Since the suggested scheme of breakdown was incomplete, enzymatic tests were carried out to clarify the matter. It was possible to carry out the first steps of breakdown also in the cell-free extract of the pyrazone-degrading bacteria. For the second step of pyrazone breakdown, 2 different enzymes of the same catalytic activity were identified. For the oxidative cleavage of the pyrocatechole derivative 2 different enzymes were found: an ortho- and a meta-clearing enzyme. The 2-hydroxy muconic acid decarboxylase was identified as a further enzyme. The importance of this enzyme is discussed in connection with the further breakdown.
Bacteria↗
Control of phosphofructokinase from rat skeletal muscle. Effects of fructose diphosphate, AMP, ATP, and citrate.
Under conditions used previously for demonstrating glycolytic oscillations in muscle extracts (pH 6.65, 0.1 to 0.5 mM ATP), phosphofructokinase from rat skeletal muscle is strongly activated by micromolar concentrations of fructose diphosphate. The activation is dependent on the presence of AMP. Activation by fructose diphosphate and AMP, and inhibition by ATP, is primarily due to large changes in the apparent affinity of the enzyme for the substrate fructose 6-phosphate. These control properties can account for the generation of glycolytic oscillations. The enzyme was also studied under conditions approximating the metabolite contents of skeletal muscle in vivo (pH 7.0, 10mM ATP, 0.1 mM fructose 6-phosphate). Under these more inhibitory conditions, phosphofructokinase is strongly activated by low concentrations of fructose diphosphate, with half-maximal activation at about 10 muM. Citrate is a potent inhibitor at physiological concentrations, whereas AMP is a strong activator. Both AMP and citrate affect the maximum velocity and have little effect on affinity of the enzyme for fructose diphosphate.
Adenosine Monophosphate↗
[Age-related properties of inductive synthesis of glucose-6-phosphatase, fructose-1,6-diphosphatase, tyrosine aminotransferase and tryptophan pyrrolase in hypothalamus stimulation].
In aged rats electrostimulation of hypothalamus caused less distinct induction of the enzymes in liver tissue, kidney and spleen as compared with the adult animals. The activation of the total RNA synthesis (actinomycin D and olivomycin) eliminated the alterations in the enzymatic activities, caused by the stimulation of hypothalamus. Effect of adrenalectomy and administration of ACTH suggested that the influence of the hypothalamus stimulation on induction of the enzymes studied was realized through the system hypophysis -- adrenal cortex. In the aged animals activation of adrenal cortex was less distinct when the stimulation of hypothalamus was carried out. The alterations in hypothalamic regulation of the enzyme induction could be an important mechanism in regulation of adaptive reactions in aged organisms.
Aging↗