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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

1. The function of mitochondria, sarcotubular membranes (heavy microsomes), sarcolemma and myofibrils from the hind-leg skeletal muscle of about 60- and 150-day-old normal and myopathic (UM-X7.1) hamsters was examined. 2. The mitochondrial calcium uptake as well as mitochondrial phosphorylation and respiratory rates were lower in 60-day-old myopathic skeletal muscle, unlike 150-day-old myopathic animals, when pyruvate-malate and glutamate-malate were used as substrates. However, mitochondria from 150-day-old myopathic animals showed depressed glutamate-dependent respiratory and phosphorylation rates and succinate-supported initial rate of calcium uptake. 3. The microsomal calcium-uptake, but not calcium-binding, and Ca2+-stimulated adenosine triphosphatase (ATPase) activity of the 150-day-old myopathic skeletal muscle were lower than the control values. Although microsomal calcium-binding, calcium-uptake and ATPase activities of the 60-day-old myopathic muscle were not depressed significantly, the initial rate of calcium uptake was less than the control. 4. The sarcolemmal Ca2+-ATPase, but not Mg2+-ATPase or Na+ +K+-ATPase, activity was higher in 60-day-old myopathic muscle whereas the activities of all these enzymes from 150-day-old myopathic animals were higher than the control. On the other hand, the Na+ +K+-ATPase activities from 60- and 150-day-old myopathic animals were inhibited by ouabain to a lesser extent in comparison with the respective control values. 5. The myofibrillar Ca2+-ATPase and Mg2+-ATPase activities as well as inhibition of Mg2+-ATPase due to Na+ and K+ in myopathic muscle were no different from the control values. 6. The results reported here give further support to the view that different membrane systems of the dystrophic muscle are defective.
Clin Sci Mol Med 1975 Oct
PMID:Defective membrane systems in dystrophic skeletal muscle of the UM-X7.1 strain of genetically myopathic hamster. 12 86

A mutation leading to partial loss of NAD-linked ("catabolic') glutamate dehydrogenase does not affect the regulation of ammonium-repressible activities in Aspergillus nidulans. This mutation has been used to show that NAD-linked glutamate dehydrogenase does not normally participate in ammonium assimilation. A mutation leading to loss of NADP-linked ("anabolic') glutamate dehydrogenase has been used to show that NADP-linked glutamate dehydrogenase is not normally involved in glutamate catabolism. Strains defective in either enzyme are useful for determining which amino acids are metabolised via transamination to yield glutamate rather than via deamination to yield ammonium.
Mol Gen Genet 1975
PMID:A mutant of Aspergillus nidulans defective in NAD-linked glutamate dehydrogenase. 17 77

The energy metabolism of rat thymus cells has been investigated using preparations of isolated cells obtained by mechanical treatment of whole organs. The addition of glycolytic substrates such as glucose, pyruvate and lactate stimulates the endogenous respiration of these cells by 50%. On the other hand, succinate, glutamate and malate do not produce any effect. Oligomycin (10 mug/ml) inhibits both endogenous and glucose stimulated respiration by about 40%; 2, 4-DNP (50 muM) increases by 100% glucose induced respiration. The results obtained by using mitochondrial and glycolytic inhibitors as well as aminoxyacetic acid (AOA) and following pyridine nucleotides redox changes, support the idea that in thymus cells glucose is able to induce a great enhancement of O2 consumption both by raising the level of endogenous pyruvate and feeding the mitochondrial respiratory chain with cytosolic reducing equivalents, through an active malate-aspartate shuttle. Thymus cells exhibit a high Pasteur effect (74%). Both AOA and 2,4 DNP are able to stimulate aerobic lactate accumulation by 200% and 100% respectively, indicating that either the redox or phosphate potential do influence the rate of aerobic glycolysis in isolated thymus cells. Similar experiments are also reported on other cells with well known biochemical characteristics.
Mol Cell Biochem 1975 Jul 31
PMID:Energy metabolism of isolated rat thymus cells. 24 Oct 10

Mutants altered in carbon catabolite regulation have been isolated by selecting for mutants of the areA217 strain capable of using acetamide as the sole nitrogen source in the presence of sucrose. In addition to creA mutants described previously be Arst and Cove, strains with mutations in two new genes, creB and cre C, have been found. The creB and creC mutants grow poorly on some sole carbon sources and have low levels of some enzymes of carbon catabolism e.g. beta-galactosidase and D-quinate dehydrogenase. The creB and creC mutants are hypersensitive to fluoroacetate, fluoroacetamide and allyl alcohol in the presence of glucose or sucrose but not glycerol; and the enzymes, acetamidase and alcohol dehydrogenase, are less sensitive to carbon catabolite repression than the wild-type strain. Extracellular protease and alpha-glucosidase enzyme activities are elevated in creB and creC mutants, while L-proline and L-glutamate uptake capacities are lower in both the presence and absence of glucose. Interactions between creA, B and C mutations have been investigated in double mutants, and the dominance properties of creB and creC mutants determined. The results indicate that the creB and creC genes may have a regulatory role in the control of carbon catabolism.
Mol Gen Genet 1977 Jan 18
PMID:Pleiotropic mutants of Aspergillus nidulans altered in carbon metabolism. 32 Apr 55

Imidazole propionic acid (ipa), a gratuitous inducer of the histidine-utilization (hut) system in Salmonella typhimurium, inhibits the organism's growth on succinate minimal medium. Induction of the hut system is necessary, but not sufficient, to cause inhibition. A study of the ability of single amino acids to relieve ipa-restricted growth suggests that insufficient glutamate is the cause of slow growth. The inhibition of growth by imidazolone propionic acid (iopa), an intermediate in the catabolism of histidine to glutamate, is similar to that by ipa. Studies using 2, 3, 5-triphenyl tetrazolium chloride plates to examine amino acid catabolism suggest that accumulation of ipa or iopa leads to inactivation of aspartate amino-transferase (AAT). This interpretation is supported by studies of an Escherichia coli mutant lacking AAT. The mutant grows poorly on succinate minimal medium, and the poor growth is relieved by the same amino acids that relieve ipa- and iopa-restricted growth. These and other findings are discussed in terms of coordination of the histidine-utilization system with enzymatic activities involved in the catabolism of other amino acids.
Mol Gen Genet 1979 Jan 05
PMID:Inhibition of growth by imidazol(on)e propionic acid: evidence in vivo for coordination of histidine catabolism with the catabolism of other amino acids. 37 43

Interaction of highly purified E. coli glutamate decarboxylase with a number substrate analogs was studied. Decarboxylation of the following amino acids was demonstrated: gamma-methylene glutamate, threo-beta-hydroxyglutamate, allo-gamma-hydroxyglutamate, threo-beta-methylglutamate, homocysteate, aminoadipate and cysteinesulfinate. The Km and either Ki or I50 values were determined for these compounds. The final products of the interaction of glutamate decarboxylase with these analogs have the same absorption spectra and capacity for reactivation by pyridoxal-P, as has the pyridoxamine-P form of the enzyme. Thus, decarboxylation of all the amino acids, mentioned above, was probably associated with the side reaction of transamination to coenzyme in the active center. Binding of aliphatic dicarboxylic acids or of valeric acid by glutamate decarboxylase leads to a slight shift of absorption spectra and of circular dichroism spectra from 420 to 423--425 nm. The following compounds fail to be bound and decarboxylated by the enzyme: gamma-aminobutyrate, D-glutamate, L-glutamine, 3,3-dimethylglutarate, methioninesulfone, methioninesulfoxide, norvaline, gamma-hydroxy-gamma-methylglutamate, erytro-beta-methylglutamate and erythro-beta-hydroxyglutamate.
Mol Biol (Mosk)
PMID:[Substrate specificity of E. coli glutamate decarboxylase]. 37 98

1. We have measured the incorporation of an intraperitoneal injection of [3H] glutamate into the protein of the gut, liver and kidney of lean and obese siblings of the genetically obese mouse. 2. Recycling of the 3H was minimized by using glutamate labelled at the C-2 position. Loss of label from the amino acid pool by transamination and deamination was rapid, with a half-life of 4 h. 3. In tissue protein the amino acid showing the highest 3H radioactivity was glutamate. 4. The half-lives for protein synthesis and catabolism were calculated from the decay curves of both specific and total radioactivity of [3H] glutamate in tissue protein. No significant differences were found between kidney, liver and gut in lean and obese mice.
Clin Sci Mol Med 1978 Apr
PMID:A new technique for measuring protein turnover in the gut, liver and kidneys of lean and obese mice with [3H] glutamic acid. 63 74

The activity of yeasts citrate synthase in cells grown under different hypoxic conditions has been investigated. A linear relationship between the citrate synthase activity and the respiratory capacity of the cells has been found. When Saccharomyces cerevisiae was grown on fermentable substrates the activity decreased as the concentration of sugars in the medium increased. The enzyme of the yeast Rhodoturula showed a high activity in spite of the existence of high sugar concentration in the culture medium. Neither feed-back repression by glutamate nor feed-forward induction by ammonia has been found in bakers' yeast. The results suggest that the regulation of the enzyme by oxygen availability takes place by the ""de novo'' synthesis of the enzyme.
Mol Cell Biochem 1976 Sep 30
PMID:Regulation of the level of yeasts citrate synthase by oxygen availability. 79 Jan 60

1. Two women with severe hypokalaemic alkalosis were investigated by means of muscle biopsy before and at the end of 2 and 3 weeks respectively of intense therapy with potassium chloride. 2. The muscle biopsy material was analysed for water, electrolytes, adenine nucleotides, phosphocreatine, free creatine, pyruvate, lactate, glycogen and free amino acids. The extra- and intra-cellular distribution of water, electrolytes and amino acids was calculated by the chloride method. 3. Both patients showed a marked loss of intracellular potassium and an increase in intracellular sodium concentration. The muscle magnesium content was also slightly decreased. After repletion with potassium chloride, muscle sodium and potassium became normal. 4. The contents of creatine phosphate, ATP, ADP, AMP, lactate and pyruvate were within normal limits, but the phosphocreatine/total creatine ratio was reduced. After repletion, a small change in the apparent creatine-phosphokinase equilibrium had occurred, suggesting a minor increase in intracellular pH. 5. The concentrations of the basic amino acids, lysine, arginine and ornithine were increased far above normal. The intracellular accumulation of arginine was much higher than the increase in lysine concentration and histidine concentration was normal. This differs from findings in potassium-depleted rats, where the intracellular lysine concentration is much higher than arginine concentration and histidine is high as well. After potassium repletion the intracellular concentration of ornithine, lysine and arginine became normal in one case and decreased considerable in the other. An increased intracellular concentration of glutamate and glutamine was also observed after potassium repletion.
Clin Sci Mol Med 1976 Dec
PMID:Influence of severe potassium depletion and subsequent repletion with potassium on muscle electrolytes, metabolites and amino acids in man. 107 Apr 23

1. Synthesis of polyglutamate derivatives from radioactively labelled folic acid, folinic acid and methotrexate has been studied in human phytohaemagglutinin-transformed lymphocytes. 2. With labelled folic acid as the precursor, approximately 20% of the labelled cell folate was found in each of the mono-, tetra-, penta- and hexaglutamate peaks after 72 h of incubation. At earlier times, the amounts of labelled folate polyglutamates were proportionately greater and the amount of labelled higher folate polyglutamates was lower. After only 4 h incubation over 80% of the intracellular labelled folate was still in the monoglutamate form. 3. With labelled folinic acid used as precursor, approximately 30% of labelled cell folate after 72 h incubation was in the form of folate pentaglutamate, with tri- and tetra-glutamate forming the other major peaks. The speed of formation of polyglutamate derivatives was substantially more rapid than from folic acid. 4. Methotrexate was found to decrease considerably the amount of folate polyglutamate formation from labelled folic acid in lymphocytes byt nevertheless some di-, tri- and traces of tetra-glutamate were formed. On the other hand, methotrexate had no effect on folate polyglutamate formation with labelled folinic acid used as the precusor. 5. Polyglutamate derivatives of labelled methotrexate were formed by human lymphocytes with mean amounts of 4-5% of di-, 1-5% of tri-, 1-0% of tetra- and 0-7% of penta-glutamate derivatives being formed over the period 48-72h of culture. 6. Pentaglutamate derivatives probably constitute the largest group of intracellular folates in human cells but a complex mixture exists. 7. The enzyme synthesizing polyglutamate derivatives of folate in human cells prefers a reduced folate as substrate but the requirement for a reduced form is not absolute. The nature of the reduced folate is uncertain but it is suggested on the basis of previous work that tetrahydrofolate rather than methylhydropfolate or any other reduced folate monoglutamate is the preferred substrate.
Clin Sci Mol Med 1976 Jan
PMID:Synthesis of folate polyglutamates in human cells. 108 4


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