Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.5.1.4 (deaminase)
 5,113 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

1. Alanine inhibits rabbit muscle AMP-deaminase while aspartate, histidine and glutamate are ineffective. 2. The degree and type of inhibition of AMP-deaminase by alanine depend on pH; at pH 6.5 alanine behaves like an allosteric effector exerting a negative heterotropic effect. At pH 7.0 the inhibition is non-competitive, Ki being as high as 19 mM. 3. The probable significance of the effect of alanine on AMP-deaminase in muscle metabolism is discussed.
 ...
PMID:Inhibition by alanine of AMP-deaminase from rabbit skeletal muscle. 0 58

A direct correlation between the absorbance of a thermophilic bacillus and specific amidase activity was observed, which was found to depend on the cell density of the culture rather than on the time of contact of the culture with the inducer. Dilution of high density cultures caused the specific amidase activity to decrease. Environmental factors such as pH, concentration of inducer or degree of aeration, and level of NH+4 and glutamate had no effect on amidase synthesis. The decrease in amidase activity upon dilution could not be ascribed to destruction by oxygen or by inactivation or decay. Several lines of evidence suggest that catabolite repression is responsible for the phenomenon described. Succinate-grown cultures gave a stronger dilution effect thatn glutamate-grown cells. The mutant strain E-21, relatively resistant to catabolite repression, did not show the characteristic dilution effect nor the direct correlation between absorbance and specific amidase activity.
 ...
PMID:Relationship between culture density and catabolite repression of an inducible aliphatic amidase in a thermophilic bacillus. 1 4

A thermophilic bacillus growing on acetamide as both carbon and nitrogen sources produces an inducible amidase. This amidase hydrolysed the following amides in decreasing order or activity, in comparison with acetamide (1.00): propionamide (0.97), fluoroacetamide (0.84), formamide (0.35) and glycinamide (0.12). Cyanoacetamide, dimethylacetamide, dimethylformamide and urea also induced the synthesis of the amidase, but were not substrates of the enzyme. Studies with protoplasts suggest that the amidase is located in the cytoplasm. Glucose strongly inhibited amidase synthesis; and limiting nitrogen did not release this inhibition. Urea strongly inhibited amidase activity in a competitive manner; but the inhibition caused by iodoacetamide and cyanoacetamide was non-competitive. Both thioacetamide and thiourea were effective inhibitors of enzyme induction. Bacteria grown on a succinate-minimal medium exhibited a lag in amidase synthesis, which could be eliminated by decreasing the concentration of succinate. Acetate- or pyruvate-grown cultures behaved similarly, while those grown on alanine or glutamate exhibited no lag in enzyme induction. In the mutant strain E21, repression of amidase synthesis by glucose was much less evident and no lag for induction was apparent with any of the other carbon sources mentioned.
 ...
PMID:Regulatory properties of an inducible aliphatic amidase in a thermophilic bacillus. 93 86

In confirmation of the findings of Gaitonde et al. (1974), a decrease in the brain concentration of threonine and serine, and an increase in glycine, were observed in rats maintained on a thiamin-deficient diet. Similar changes were found in the blood, and the concentration of several other amino acids in the blood decreased significantly. There was a correlation between the concentrations of threonine, serine, aspartate and asparagine in the brain and blood. In experiments in which [U-14C]threonine was injected into rats most of the radioactivity in the brain and blood of control rats was, as expected, in threonine in the acid soluble metabolites. In contrast, a considerable proportion of radioactivity was also found in other amino acids, namely glutamate, glutamine, aspartate, gamma-aminobutyrate and alanine, in the brain of thiamin-deficient rats. [U-14C]Threonine was also converted into 14C-labelled lactate and glucose, but the extent of this conversion was severalfold higher in thiamin-deficient than in control rats. This finding gave evidence of the stimulation in thiamin-deficient rats of the catabolism of [U-14C]threonine to [14C]lactate by the aminoacetone pathway catalysed by threonine dehydrogenase, and into succinate via propionate by the alpha-oxobutyrate pathway catalysed by threonine dehydratase (deaminase). The measurement of specific radioactivities of glutamate, aspartate and glutamine after injection of [U-14C]threonine, indicated a stimulation of the activities of threonine dehydrogenase and threonine dehydratase (deaminase) in the brain of thiamin-deficient rats. The specific radioactivities of glutamate, asparatate and glutamine int he brain were consistent with an alteration in the metabolism of threonine, mainly in the 'large' compartment of the brain of thiamin-deficient rats. The measurement of relative specific radioactivity of proteins after injection of [U-14C]threonine indicated a marked decrease in the synthesis of proteins, mainly in the liver of thiamin-deficient rats.
 ...
PMID:Conversion of [U-14C]threonine into 14C-labelled amino acids in the brain of thiamin-deficient rats. 118 Sep 21

Beijerinckia indica var. penicillanicum mutant UREMS-5, producing 168% more penicillin V acylase, was obtained by successive treatment with UV, gamma-irradiation and ethylmethane sulfonate. Penicillin V acylase production by the mutant strain was resistant to catabolite repression by glucose. Incorporation of glucose, sodium glutamate and vegetable oils in the medium enhanced enzyme production. The maximum specific production of penicillin V acylase was 244 IU/g dry weight of cells. Effect of solvents on hydrolysis of penicillin V by soluble penicillin V acylase and whole cells was studied. Methylene chloride, chloroform and carbon tetrachloride significantly stimulated the rate of penicillin V hydrolysis by whole cells.
 ...
PMID:Beijerinckia indica var. penicillanicum penicillin V acylase: enhanced enzyme production by catabolite repression-resistant mutant and effect of solvents on enzyme activity. 136 9

N-Acetyl-L-glutamate has been examined with regard to its ability to activate carbamoyl phosphate synthetase I (EC 6.3.4.16). Substance(s) inhibitory to carbamoyl phosphate synthetase, present even in the partially purified preparation of rat liver extracts, interfered with the measurement of acetylglutamate. In the experiments using chelating agents, metals were apparently involved in this inhibition. When the partially purified preparation of liver extract was placed on a Chelex 100 column, the inhibitor was eliminated and accurate measurements of acetylglutamate content could be made. Evidence supporting the validity of this improved method is given. A significant difference was observed between acetylglutamate levels determined by the present method and by the one using aminoacylase I (N-acylamino acid amidohydrolase, EC 3.5.1.14) to hydrolyze acetylglutamate followed by assay of the glutamate generated. We searched for the presence of glutamate derivatives other than acetylglutamate. When impure tissue preparations containing acetylglutamate were treated with a commercial preparation of aminoacylase, there was an excess amount of glutamate apparently derived from compounds other than acetylglutamate. This can lead to an overestimation of the tissue levels of acetylglutamate.
 ...
PMID:An improved method for determination of N-acetyl-L-glutamate by its function as an activator of carbamoyl phosphate synthetase I. 230 60

With the use of a continuous spectrophotometric assay and initial rates determined by the method of Waley [Biochem. J. (1981) 193, 1009-1012] methotrexate was found to be a non-competitive inhibitor, with Ki(intercept) = 72 microM and Ki(slope) = 41 microM, of 5-aminoimidazole-4-carboxamide ribotide transformylase, whereas a polyglutamate of methotrexate containing three gamma-linked glutamate residues was a competitive inhibitor, with Ki = 3.15 microM. Pentaglutamates of folic acid and 10-formylfolic acid were also competitive inhibitors of the transformylase, with Ki values of 0.088 and 1.37 microM respectively. Unexpectedly, the pentaglutamate of 10-formyldihydrofolic acid was a good substrate for the transformylase, with a Km of 0.51 microM and a relative Vmax. of 0.72, which compared favourably with a Km of 0.23 microM and relative Vmax. of 1.0 for the tetrahydro analogue. An analysis of the progress curve of the transformylase-catalysed reaction with the above dihydro coenzyme revealed that the pentaglutamate of dihydrofolic acid was a competitive product inhibitor, with Ki = 0.14 microM. The continuous spectrophotometric assay for adenosine deaminase based on change in the absorbance at 265 nm was shown to be valid with adenosine concentrations above 100 microM, which contradicts a previous report [Murphy, Baker, Behling & Turner (1982) Anal. Biochem. 122, 328-337] that this assay was invalid above this concentration. With the spectrophotometric assay, 5-aminoimidazole-4-carboxamide riboside was found to be a competitive inhibitor of adenosine deaminase, with (Ki = 362 microM), whereas the ribotide was a competitive inhibitor of 5'-adenylate deaminase, with Ki = 1.01 mM. Methotrexate treatment of susceptible cells results in (1) its conversion into polyglutamates, (2) the accumulation of oxidized folate polyglutamates, and (3) the accumulation of 5-aminoimidazole-4-carboxamide riboside and ribotide. The above metabolic events may be integral elements producing the cytotoxic effect of this drug by (1) producing tighter binding of methotrexate to folate-dependent enzymes, (2) producing inhibitors of folate-dependent enzymes from their tetrahydrofolate coenzymes, and (3) trapping toxic amounts of adenine nucleosides and nucleotides as a result of inhibition of adenosine deaminase and 5'-adenylate deaminase respectively.
 ...
PMID:Inhibition of 5-aminoimidazole-4-carboxamide ribotide transformylase, adenosine deaminase and 5'-adenylate deaminase by polyglutamates of methotrexate and oxidized folates and by 5-aminoimidazole-4-carboxamide riboside and ribotide. 243 76

Two subsequent phases of hepatogenic encephalopathy (HE), the metabolic and precomatous phase, were produced in rats by thioacetamide treatment. Plasma and brain levels of arginine and its metabolites in the arginine-glutamate pathway, and activities of 2 brain enzymes of this pathway: arginase (L-arginine amidohydrolase, EC3521) and ornithine amino-transferase (OAT, ornithine-oxo-acid aminotransferase, EC26113) were measured in these rats. Plasma arginine sharply decreased in the metabolic phase and rose above control level in the precomatous phase, whereas ornithine and glutamate increased and urea decreased in both phases. Brain amino acids levels remained unchanged throughout, confirming earlier report of their insensitivity to external manipulation. Both brain enzymes showed a similar stepwise increase in their activities up to 150% the control level. The results are indicative of increased involvement of arginine as a precursor of amino acid neurotransmitters glutamate and GABA, with possible implication for the course of HE.
 ...
PMID:Arginine in thioacetamide-induced hepatogenic encephalopathy in rats: activation of enzymes of arginine metabolism to glutamate. 287 5

Formylglutamate amidohydrolase (FGase) catalyzes the terminal reaction in the five-step pathway for histidine utilization in Pseudomonas putida. By this action, N-formyl-L-glutamate (FG) is hydrolyzed to produce L-glutamate plus formate. Urocanate, the first product in the pathway, induced all five enzymes, but FG was able to induce FGase alone, although less efficiently than urocanate did. This induction by FG resulted in the formation of an FGase with electrophoretic mobility identical to that of the FGase induced by urocanate. A 9.6-kilobase-pair HindIII DNA fragment containing the P. putida FGase gene was cloned into the corresponding site on plasmid pBEU1 maintained in Escherichia coli. Insertion of the fragment in either orientation on the vector resulted in expression, but a higher level was noted in one direction, suggesting that the FGase gene can be expressed from either of two vector promoters with different efficiencies or from a single vector promoter in addition to a less efficient Pseudomonas promoter. FGase was purified 1,110-fold from the higher-expression clone in a yield of 10% through six steps. Divalent metal ions stimulated activity, and among those tested (Co, Fe, Zn, Ca, Ni, Cd, Mn, and Mg), Co(II) was the best activator, followed by Fe(II). FGase exhibited a Km of 14 mM for FG and a specific activity of 100 mumol/min per mg of protein in the presence of 5 mM substrate and 0.8 mM CoCl2 at 30 degrees C. The enzyme was maximally active in the range of pH 7 to 8. FGase was found to be a monomer of molecular weight 50,000. N-Acetyl-L-glutamate was not a substrate for the enzyme, but both it and N-formyl-L-aspartate were competitive inhibitors of formylglutamate hydrolysis, exhibiting Ki values of 6 and 9 mM, respectively. The absence of FGase activity as an integral part of histidine breakdown in most other organisms and the somewhat uncoordinated regulation of FGase synthesis with that of the other hut enzymes in Pseudomonas suggest that the gene encoding its synthesis may have evolved separately from the remaining hut genes.
 ...
PMID:Purification and properties of formylglutamate amidohydrolase from Pseudomonas putida. 330 50

Partial denaturation of the circular octameric bifunctional enzyme formiminotransferase-cyclodeaminase in increasing urea concentrations leads to sequential dissociation via dimers to inactive monomers. In potassium phosphate buffer, dissociation to dimers in 3 M urea coincides with loss of both activities and a major decrease in intensity of intrinsic tryptophan fluorescence. In the presence of folic acid, these dimers retain the deaminase activity, but with folylpolyglutamates, both activities are protected and the native octameric structure is retained. The protection profiles with polyglutamates are cooperative with a Hill coefficient greater than 2, suggesting that binding of more than one folylpolyglutamate per octamer is required to stabilize the native structure. In triethanolamine hydrochloride buffer, transferase-active dimers that retain the intrinsic tryptophan fluorescence can be obtained in 1 M urea and stabilized at higher urea concentration by the addition of glutamate. Deaminase-active dimers are obtained by the protection of folate in 3 M urea. Proteolysis of the two kinds of dimers by chymotrypsin leads to very different fragmentation patterns, indicating that they are structurally different. We propose that the two dimers retain different subunit-subunit interfaces, one of which is required for each activity. This suggests that the native octameric structure is required for expression of both activities and therefore for "channeling" of intermediates.
 ...
PMID:Dissociation of the octameric bifunctional enzyme formiminotransferase-cyclodeaminase in urea. Isolation of two monofunctional dimers. 359 1


1 2 3 4 5 6 7 8 Next >>