Escherichia enzyme action

Cervera and Levine [81] studied the mechanism of oxidative modification of glutamine synthetase from Escherichia coli. It was found that active oxygen species initially caused inactivation of the enzyme and generated a more hydrophilic protein, which still was not a substrate for the protease. Continuous action of oxygen species resulted in the formation of oxidized protein subjected to the proteolytic attack of protease. 

Sancar GB, Jorns MS, Payne G, Fluke DJ, Rupert CS, Sancar A 1987a Action mechanism of Escherichia coli DNA photolyase. III. Photolysis of the enzyme-substrate complex and the absolute action spectrum. J Biol Chem 262 492-498 Sancar GB, Smith FW, Reid R, Payne G, Levy M, Sancar A 1987b Action mechanism of Escherichia coli DNA photolyase. I. Formation of the enzyme-substrate complex. J Biol Chem 262 478-485... 

Mechanism of Action An antitubercular that inhibits DNA-dependent RNA polymerase, an enzyme in susceptible strains of Escherichia coli and Bacillus subtilis. Rifabutin has a broad spectrum of antimicrobial activity including against mycobacteria such as Mycobacterium avium complex (MAC). Therapeutic Effect Prevents MAC disease. 

The N-acetylneuraminic acid derivative 44 is widely distributed. It was isolated from a strain182 of Escherichia coli, and has been obtained from cytidine 5 -triphosphate and N-acetylneuraminic acid by the action of enzyme preparations from Neisseria meningitidis183 and from animal tissues.184-186 The latter enzyme can also make use of N-glycolylneuraminic acid as a substrate, to give the respective cytidine 5 -phosphate derivative. 

Suzuki et al. examined the effect of various divalent cations on purified recombinant human GCH expressed in Escherichia coli to clarify the molecular mechanism of action of divalent cations on the GCH enzymatic activity [150]. They demonstrated that GCH utilizes metal-free GTP as the substrate for the enzyme reaction. Inhibition of the GCH activity by divalent cations such as Mg(II) and Zn(II) was due to a reduction in the concentration of metal-free GTP substrate by complex formation. Many nucleotidehydrolyzing enzymes such as G proteins and kinases recognize Mg-GTP or Mg-ATP complex as their substrate. In contrast with these enzymes, Suzuki et al. demonstrated that GCH activity is dependent on the concentration of Mg-free GTP [150]. 

A Sugino, CL Peebles, KN Kreuzer, NR Cozzarelli. Mechanism of action of nalidixic acid purification of Escherichia coli nalA gene product and its relationship to DNA gyrase and a novel nicking-closing enzyme. Proc Natl Acad Sci (USA) 74 4767-4771, 1977. 

The NADP-IDH from Escherichia coli has been thoroughly studied. It is a dimeric protein of two identical 40-kDa subunits. High-resolution X-ray crystal structures have been determined for the enzyme with and without substrate [16,17], and for the pseudo-Michaelis complex of the enzyme with isocitrate and NADP [18], Structures of sequential intermediates formed during the catalytic action of IDH are also available [19], Additionally, the kinetic and catalytic mechanisms have been determined in detail [20], Amino acid residues which are involved in interactions with substrate, coenzyme, metal ions, and catalysis have been identified [10,21],... 

Enzyme inhibition can be reversed by supplementation of arginine or citrulline.34 106 Pathovars of P. syringae were shown to inhibit Escherichia coli growth, an effect reversed by L-arginine, but not by L-citrulline or L-glutamine.121 This suggested that the site of action of the toxin produced is involved in the conversion of citrulline to arginine in the urea cycle. 

M. A. Nesmeyanova, O. B. Maraeva, A. I. Severin, E. I. Zaichkin and I. S. Kulaev (1976). The action of detergents and proteolytic enzymes on membrane bound polyphosphohydrolases in cells of Escherichia coli with repressed and de-repressed biosynthesis of these enzymes. Biokhimiya (Moscow), 41, 1256-1262. 

The 3-galactosidase of Escherichia coli, ML 309, was the first of the class of oligosaccharide-splitting enzymes to be obtained in pure and crystalline form. It is, therefore, well suited for studies on the mechanism of its action. 

Gilbert P, Beveridge EG, Crone PB. The action of phenoxyethanol upon respiration and dehydrogenase enzyme systems in Escherichia coli. J Pharm Pharmacol 1976 28 (Suppl.) 51P. 

Gwyer, J.D., Richardson, D.J., and Butt, J.N. (2006) Inhibiting Escherichia coli cytochrome c nitrite reductase voltammetry reveals an enzyme equipped for action despite the chemical challenges it may face in vivo. 

L-Asparaginase is unique among cytotoxic drugs in its unusual mechanism of action, patterns of toxicity, and source (see Table 124—15). It is an enzyme produced by Escherichia coli and other bacteria. 

Another enzyme for which X-ray diffraction studies have aided in an analysis of the mode of action is the enzyme dihydrofolate reductase. This catalyzes the reduction of 7,8-dihydrofolate to 5,6,7,8-tetrahydrofolate, an essential coenzyme used in the synthesis of thymidylate, inosinate, and methionine. The antitumor agent methotrexate is a powerful inhibitor of dihydrofolate reductase, causing, on binding, a cellular deficiency of thymidylate (the cause of its antitumor activity). The crystal structures of the enzyme from two bacterial sources—Escherichia coli and Lactobacillus casei—and from chicken liver have been studied (88-90). Both the E. coli and L casei enzymes have been studied as complexes with methotrexate bound at the active site, and, in the case of the . casei enzyme, the cofactor, NADPH, was also present. 

The utility of this methodology is illustrated by the stereoselective synthesis of ( + )-cer-ulenin (759), an antifungal antibiotic first isolated from the culture filtrate of Cephalosporium caerulens. Its ability to inhibit lipid biosynthesis in Escherichia coli by irreversibly binding P-keto-acyl-carrier protein synthetase, the enzyme responsible for the chain lengthening reaction in fatty acid synthesis, has attracted interest in its mechanism of action. D-Tartaric acid... 

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