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)

1) A lysosomal protease, a new cathepsin that inactivates glucose-6-phosphate dehydrogenase [EC 1.1.1.49] and some other enzymes and differs from cathepsin B [EC 3.4.22.1] was purified about 2,200-fold from crude extracts of rat liver by cell-fractionation, freezing and thawing, acetone treatment, gel filtration, and DEAE Sephadex and CM-Sephadex column chromatographies. 2) The new cathepsin was markedly activated by the thiol-reagent, 2-mercaptoethanol and inhibited by monoiodoacetate. 3) The molecular weight of the new cathepsin was found by Sephadex G-75 column chromatography to be 22,000, which is smaller than that of cathepsin B. 4) The optimum pH of the enzyme for inactivation of glucose-6-phosphate dehydrogenase was pH 5.0--5.5. The enzyme was unstable in alkali and on heat treatment. 5) The rates of inactivation of glucose-6-phosphate dehydrogenase, apo-ornithine aminotransferase [EC 2.6.1.13], apo-tyrosine aminotransferase [EC 2.6.1.5], apo-cystathionase [EC 4.4.1.1], glucokinase [EC 2.7.1.2], glyceraldehyde-3-phosphate dehydrogenase [EC 1.2.1.12], and malate dehydrogenase [EC 1.1.1.37] by the new cathepsin were higher than those by cathepsin B. However aldolase [EC 4.1.2.13] was inactivated more rapidly by cathepsin B than by the new cathepsin. Lactate dehydrogenase [EC 1.1.1.27], glutamate dehydrogenase [EC 1.4.1.2] and alcohol dehydrogenase [EC 1.1.1.1] were not inactivated by either cathepsin. Unlike cathepsin B, the new cathepsin scarcely hydrolyzes N-substituted derivatives of arginine.
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PMID:Purification and properties of a new cathepsin from rat liver. 3 59

Biotin deficiency resulted in an increased growth rate of Aspergillus nidulans. The activities of hexokinase and aldolase were not much changed during the growth cycle, but activities of glucose-6-phosphate dehydrogenase and NADP-linked glutamate dehydrogenase increased significantly during the exponential phase. This change was remarkable during biotin deficiency. In contrast to the higher growth rate and respiration rate during biotin deficiency the activities of NAD(P)H oxidoreductases were low. An inverse relationship between the activity of tyrosinase and melanin content was observed. A role of the DOPA-DOPA-quinone system in maintaining culture growth is suggested.
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PMID:Growth, glucose metabolism and melanin formation in biotin-deficient Aspergillus nidulans. 40 7

The hepatocyte and haematopoietic cell contents of the liver of the foetal guinea pig were measured over the latter half of gestation. Hepatocytes represented about 30% of liver volume at mid-gestation and this increased to 70-80% by term; cell volume remained fairly constant until 5-7 days before term, then more than doubled. Haematopoietic cells represented about 5% of liver volume at mid-gestation and this progressively fell to <1% by term. At 75% of gestation hepatocytes and haematopoietic cells were prepared from perfused foetal livers by collagenase digestion. Enzyme activity of the hepatocyte was, without exception, similar to that of the whole liver. In general, enzyme activity in the haematopoietic cells was similar to that in erythrocytes, with relatively low values for aldolase, glycerol 3-phosphate dehydrogenase, phosphoglycerate mutase, enolase, lactate dehydrogenase, phosphoenolpyruvate carboxykinase, fructose 1,6-bisphosphatase, isocitrate dehydrogenase, ;malic' enzyme, glutamate dehydrogenase and aspartate aminotransferase. The haematopoietic cell contribution to total enzyme activity in the foetal liver was usually much less than 10% and could thus not account for the major changes in hepatic enzyme activity over the latter half of gestation. Hepatocytes contained hexokinase isoenzymes I and III, aldolase isoenzymes A and B and pyruvate kinase isoenzymes 1, 2 and 4. The haematopoietic cells contained hexokinase isoenzyme I and two additional bands of activity with slightly greater mobility, aldolase isoenzyme A and pyruvate kinase isoenzymes 2 and 4.
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PMID:The distribution of enzyme and isoenzyme activities between parenchymal and haematopoietic cells in the liver of the foetal guinea pig. 43 88

The rate of distribution of cell enzymes between the intravascular and extravascular space was studied, following a sudden decrease of enzyme activities in plasma. This rapid decrease of enzyme activities was achieved in rats by a rapid exchange of the blood with a twofold volume of a suspension of homologous erythrocytes in isoosmolar bovine serum albumin solution. After this plasmapheresis, the activities of seven cell enzymes in the plasma were decreased to 14 to 22% of their original values. The subsequent increase in activities showed different kinetics, depending on the enzyme. After 120 min, creatine kinase had reached the starting activity; malate dehydrogenase and aldolase reached their original activities after 180 min. Aspartate aminotransferase, glutamate dehydrogenase, alanine aminotransferase and pyruvate kinase increased more slowly and they had still not reached their starting values after 240 min. Repetition of the plasmapheresis after 90 min had no obvious effect on the kinetics of the subsequent activity increase. During the first minutes after plasmapheresis the adjustment of the activity equilibrium between the interstitial and the intravascular compartments depends mainly on the capillary permeability. It is therefore possible to determine half-life constants for the distribution of enzymes within the extracellular space. The constants for malate dehydrogenase and aldolase are almost identical with those determined by intravenous injection, whereas there are discrepancies in the constants for the remaining enzymes. The constants for pyruvate kinase and glutamate dehydrogenase are significantly lower, while those for aspartate aminotransferase, alanine aminotransferase and creatine kinase are significantly higher, than those determined after intravenous injection. Possible reasons for these differences are disucssed.
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PMID:[Plasmapheresis as an experimental model for studies on the extracellular distribution of enzymes. Distribution and transport of cell enzymes within the extracellular space. IV (author's transl)]. 93 47

In the subcommissural organ (SCO) of the guinea pig, rat, golden hamster, and mouse the activity and distribution of enzymes related to the energy-supplying metabolism and of some marker enzymes of different cell organelles have been investigated by means of mostly modified histochemical methods. The results were compared with findings in the ciliated ependyma of the ventricular wall and with those in the ependyma of the choroid plexus of the third ventricle. In the ependymal part of the SCO only a moderate activity of hexokinase is observed in its specialized columnar cells whereas a high activity is present both in the ciliated ependyma and the choroid plexus. - The staining pattern of glucose-6-phosphatase is similar to that of hexokinase but this enzyme is found is the SCO only. - Likewise hexokinase, glycogen granules and enzymes related to glycogen metabolism (phosphoglucomutase, uridine-diphosphoglucose pyrophosphorylase, glycogen synthetase and phosphorylase) are regularly found most numerous and active in the nuclear and supra-nuclear area of the ependymal part. These enzymes are less active in both the other ependymal regions. - Uridine-diphosphoglucose dehydrogenase could not be demonstrated in the SCO. The NADP-linked enzymes of the pentose phosphate shunt, glucose-6-phosphate and 6-phosphogluconate dehydrogenase, show a moderate activity which decreases also from the nuclear towards the apical area of the ependymal cells of the SCO. Enzymes of the glycolytic pathway, such as glucosephosphate isomerase, fructose-6-phosphate kinase, fructose-I,6-diphosphate aldolase, glyceraldehyde-3-phosphate and lactate dehydrogenase, are highly active in the SCO and are located mainly in the supranuclear area, too. Fructose-1,6-diphosphatase could not be demonstrated thus indicating that in the SCO the pathway is most probably only glycolytic but not gluconeogenetic. Compared to the ependyma of the ventricular wall and of the choroid plexus, in the SCO the M type subunits of lactate dehydrogenase predominate. Glycolytic enzymes are also very active in the choroid plexus but less in the ciliated ependyma. Compared to the ciliated ependyma and especially to the ependyma of the choroid plexus, the activities of enzymes which are only present in mitochondria (NAD-linked isocitrate dehydrogenase, succinate dehydrogenase, NAD-linked malate dehydrogenase after preextraction, cytochrome oxidase, 3-hydroxybutyrate and glycerolphosphate and glutamate dehydrogenase) are relatively low. Mitochondria are accumulated near the superior pole of the nuclei as well as in the most apical part of the ependymal cells. - The staining pattern of NADP-linked isocitrate and malate dehydrogenase as well as of NADH dehydrogenase suggests that these enzymes are localized both in and out of mitochondria. The extramitochondrial activity of the first two enzymes might be localized in the cytosol. The extramitochondrial activity of NADH dehydrogenase might be localized in the endoplasmic reticulum...
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PMID:Enzymatic organization of the subcommissural organ. 123 49

It is well established that caloric restriction extends life span and significantly retards the rate of occurrence of most age-associated degenerative disease processes. A paucity of data exists relative to the mechanisms by which caloric restriction accomplishes these events. We have examined the effect of caloric restriction in rats on several hepatic enzymes of intermediary metabolism. The activities of glycolytic and supporting enzymes including lactate dehydrogenase, pyruvate kinase, sorbitol dehydrogenase, and alcohol dehydrogenase were all decreased in response to caloric restriction. Fructose 1-phosphate aldolase and creatine phosphokinase were not altered. Likewise, enzymes associated with lipid metabolism (malic enzyme and glycerokinase) were reduced (fatty acid synthetase was reduced, but not to a statistically significant degree). Activities of enzymes supporting gluconeogenesis (glutamate oxaloacetate transaminase, tyrosine aminotransferase, glutamate pyruvate transaminase, glutamate dehydrogenase, amino acid oxidase, malate dehydrogenase, and glucose 6-phosphatase) were either unchanged or increased significantly by caloric restriction. Glucagon levels were decreased. Comparisons between young ad libitum fed and older calorically restricted rats revealed similar but not identical metabolic activity. These results suggest that caloric restriction produces an effect on intermediary metabolism, favoring the role of glucagon and glucose synthesis; but limiting the role of insulin and glucose catabolism in the liver. The former observation provides for the efficient support of peripheral tissues and the latter a level of energy production necessary only for self maintenance. Limited lipid metabolism suggests decreased potential for fatty acid epoxide formation and free radical damage to cellular macromolecules. Additionally, caloric restriction may delay the progressive age associated changes in the activities of some of the enzymes investigated.
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PMID:Effect of chronic caloric restriction on hepatic enzymes of intermediary metabolism in the male Fischer 344 rat. 266 33

Energy metabolism in proliferating cultured rat thymocytes was compared with that of freshly prepared non-proliferating resting cells. Cultured rat thymocytes enter a proliferative cycle after stimulation by concanavalin A and Lymphocult T (interleukin-2), with maximal rates of DNA synthesis at 60 h. Compared with incubated resting thymocytes, glucose metabolism by incubated proliferating thymocytes was 53-fold increased; 90% of the amount of glucose utilized was converted into lactate, whereas resting cells metabolized only 56% to lactate. However, the latter oxidized 27% of glucose to CO2, as opposed to 1.1% by the proliferating cells. Activities of hexokinase, 6-phosphofructokinase, pyruvate kinase and aldolase in proliferating thymocytes were increased 12-, 17-, 30- and 24-fold respectively, whereas the rate of pyruvate oxidation was enhanced only 3-fold. The relatively low capacity of pyruvate degradation in proliferating thymocytes might be the reason for almost complete conversion of glucose into lactate by these cells. Glutamine utilization by rat thymocytes was 8-fold increased during proliferation. The major end products of glutamine metabolism are glutamate, aspartate, CO2 and ammonia. A complete recovery of glutamine carbon and nitrogen in the products was obtained. The amount of glutamate formed by phosphate-dependent glutaminase which entered the citric acid cycle was enhanced 5-fold in the proliferating cells: 76% was converted into 2-oxoglutarate by aspartate aminotransferase, present in high activity, and the remaining 24% by glutamate dehydrogenase. With resting cells the same percentages were obtained (75 and 25). Maximal activities of glutaminase, glutamate dehydrogenase and aspartate aminotransferase were increased 3-, 12- and 6-fold respectively in proliferating cells; 32% of the glutamate metabolized in the citric acid cycle was recovered in CO2 and 61% in aspartate. In resting cells this proportion was 41% and 59% and in mitogen-stimulated cells 39% and 65% respectively. Addition of glucose (4 mM) or malate (2 mM) strongly decreased the rates of glutamine utilization and glutamate conversion into 2-oxoglutarate by proliferating thymocytes and also affected the pathways of further glutamate metabolism. Addition of 2 mM-pyruvate did not alter the rate of glutamine utilization by proliferating thymocytes, but decreased the rate of metabolism beyond the stage of glutamate significantly. Formation of acetyl-CoA in the presence of pyruvate might explain the relatively enhanced oxidation of glutamate to CO2 (56%) by proliferating thymocytes.
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PMID:Glutamine and glucose metabolism during thymocyte proliferation. Pathways of glutamine and glutamate metabolism. 286 9

Effect of naphthoquinone levels on the activity of enzymes involved in glycolysis and pentose phosphate cycles was studied in male rats. Under conditions of primary and secondary K-avitaminosis the enzymatic activity, limiting these cycles, (aldolase of fructose-1,6-diphosphate, glucose phosphate isomerase and glucose-6-phosphate dehydrogenase) was increased, while the mitochondrial glutamate dehydrogenase activity was decreased. As a result of metabolic transformations under conditions of K-avitaminosis (primary and secondary) concentration of DNA in the animal tissues was lowered.
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PMID:[The effect of vitamin K on the activity of glycolysis and pentose phosphate cycle enzymes]. 342 Aug 14

Joyner, A. E., Jr. (University of California, Davis), and R. L. Baldwin. Enzymatic studies of pure cultures of rumen microorganisms. J. Bacteriol. 92:1321-1330. 1966.-The activities of enzymes representing the major pathways of carbohydrate metabolism and anaerobic electron transport in cell-free extracts of whole rumen contents have been reported. The effects of diet upon the activities of several enzymes suggested that enzymatic measurements might prove useful for the study of rumen metabolism. In the present study, the distribution and characteristics of aldolase, succinate dehydrogenase, glutamate dehydrogenase, lactyl-coenzyme A dehydrase, lactate dehydrogenase, and other enzymes were measured in cell-free extracts of pure cultures of Ruminococcus flavefaciens, R. albus, Bacteroides succinogenes, B. ruminicola, B. amylophilus, Butyrivibrio fibrisolvens, Peptostreptococcus elsdenii, Streptococcus bovis, and Selenomonas ruminantium. Some enzymes were widely distributed (aldolase, glutamate dehydrogenase), whereas others were observed in one or two species (lactyl-coenzyme A dehydrase). The cofactor requirements and kinetic characteristics of enzymes varied considerably with species. Enzymes that vary with species might be employed as indices for estimating the activities of various groups of microorganisms in whole rumen contents.
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PMID:Enzymatic studies of pure cultures of rumen microorganisms. 438 Aug 1

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


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