scholarly journals Kinetic studies of allosteric catabolic ornithine carbamoyltransferase from Pseudomonas aeruginosa

1998 ◽  
Vol 251 (1-2) ◽  
pp. 528-533 ◽  
Author(s):  
Germaine Sainz ◽  
Catherine Tricot ◽  
Marie-Francoise Foray ◽  
Dominique Marion ◽  
Otto Dideberg ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Kinetic Studies ◽  
Ornithine Carbamoyltransferase

scholarly journals The Global Arginine Regulator ArgR Controls Expression of argF in Pseudomonas syringae pv. phaseolicola but Is Not Required for the Synthesis of Phaseolotoxin or for the Regulated Expression of argK

2004 ◽  
Vol 186 (11) ◽  
pp. 3653-3655 ◽  
Author(s):  
José Luis Hernández-Flores ◽  
Karina López-López ◽  
Rogelio Garcidueñas-Piña ◽  
Alba E. Jofre-Garfias ◽  
Ariel Alvarez-Morales
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Pseudomonas Syringae ◽  
Ornithine Carbamoyltransferase ◽  
Regulated Expression

ABSTRACT In Pseudomonas syringae pv. phaseolicola the enzyme ornithine carbamoyltransferase (OCTase), encoded by argF, is negatively regulated by argR, similar to what has been reported for Pseudomonas aeruginosa. However, production of the phaseolotoxin-resistant OCTase encoded by argK, synthesis of phaseolotoxin, and infectivity for bean pods occur independently of the ArgR protein.

A More Sensitive Automated Method for Determination of Ornithine Carbamoyltransferase Activity in Human Serum

1975 ◽  
Vol 21 (6) ◽  
pp. 754-757 ◽  
Author(s):  
Kathleen J Clayson ◽  
James S Fine ◽  
Paul E Strandjord
Keyword(s):  
Kinetic Studies ◽  
Sample Volume ◽  
Ornithine Carbamoyltransferase ◽  
Hepatocellular Injury ◽  
Carbamoyl Phosphate ◽  
Automated Method ◽  
Upper Limit ◽  
Threefold Increase ◽  
Assay Conditions

Abstract Ornithine carbamoyltransferase (EC 2.1.3.3) activity is a sensitive, specific indicator of hepatocellular injury. This paper describes development of an improved automated procedure for measurement of this activity. Triethanolamine—ethylenedlaminetetraacetate is used as a buffer, and activity is determined by measuring the concentration of the product, citrulline. Kinetic studies have been performed to determine optimal pH and L-ornithine and carbamoyl phosphate concentrations. Recovery of citrulline was studied. The upper limit of normal obtained in a study of 106 blood-bank donors was 6 U/liter. The automated procedure developed as a result of these studies, in which optimal assay conditions are used, produces a threefold increase in sensitivity and permits use of a sample volume of 1 ml.

scholarly journals Investigation of the mating system ofPseudomonas aeruginosastrain 1: I. Kinetic studies

1968 ◽  
Vol 12 (1) ◽  
pp. 29-36 ◽  
Author(s):  
J. S. Loutit ◽  
L. E. Pearce ◽  
M. G. Marinus
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Mating System ◽  
Genetic Material ◽  
Kinetic Studies ◽  
Potassium Nitrate ◽  
Donor Cells

A method has been developed which will permit the mapping of the genetic material ofPseudomonas aeruginosa. This has been made possible by the use of potassium nitrate in the mating medium and other modifications which have increased the frequency of recombination. In certain circumstances, theilvA12marker may be transferred by more than 1% of the donor cells.

scholarly journals Class D β-Lactamases: Are They All Carbapenemases?

2014 ◽  
Vol 58 (4) ◽  
pp. 2119-2125 ◽  
Author(s):  
Nuno T. Antunes ◽  
Toni L. Lamoureaux ◽  
Marta Toth ◽  
Nichole K. Stewart ◽  
Hilary Frase ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Pseudomonas Aeruginosa ◽  
Clinical Importance ◽  
Kinetic Studies ◽  
Resistance Pattern ◽  
Content Type ◽  
Narrow Spectrum ◽  
Class D ◽  
Life Threatening

ABSTRACTCarbapenem-hydrolyzing class D β-lactamases (CHDLs) are enzymes of the utmost clinical importance due to their ability to produce resistance to carbapenems, the antibiotics of last resort for the treatment of various life-threatening infections. The vast majority of these enzymes have been identified inAcinetobacterspp., notably inAcinetobacter baumannii. The OXA-2 and OXA-10 enzymes predominantly occur inPseudomonas aeruginosaand are currently classified as narrow-spectrum class D β-lactamases. Here we demonstrate that when OXA-2 and OXA-10 are expressed inEscherichia colistrain JM83, they produce a narrow-spectrum antibiotic resistance pattern. When the enzymes are expressed inA. baumanniiATCC 17978, however, they behave as extended-spectrum β-lactamases and confer resistance to carbapenem antibiotics. Kinetic studies of OXA-2 and OXA-10 with four carbapenems have demonstrated that their catalytic efficiencies with these antibiotics are in the same range as those of some recognized class D carbapenemases. These results are in disagreement with the classification of the OXA-2 and OXA-10 enzymes as narrow-spectrum β-lactamases, and they suggest that other class D enzymes that are currently regarded as noncarbapenemases may in fact be CHDLs.

Purification, crystallization and preliminary X-ray analysis of catabolic ornithine carbamoyltransferase from Pseudomonas aeruginosa

1999 ◽  
Vol 55 (9) ◽  
pp. 1591-1593 ◽  
Author(s):  
G. Sainz ◽  
J. Vicat ◽  
R. Kahn ◽  
C. Tricot ◽  
V. Stalon ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Point Group ◽  
Unit Cell ◽  
Group Symmetry ◽  
Ornithine Carbamoyltransferase ◽  
Unit Cell Parameters ◽  
Crystal Forms ◽  
Space Group ◽  
Cell Parameters ◽  
Hexagonal Crystals

The catabolic ornithine carbamoyltransferase (OTCase) from Pseudomonas aeruginosa exhibits allosteric behaviour, with two conformational states of the molecule: an active R form and an inactive T form. The enzyme is a dodecamer with a molecular mass of 455700 Da. Three crystal forms have been obtained. Crystals of allosteric state T are rhombohedral, belonging to the R3 space group, with hexagonal unit-cell parameters a = b = 180.6, c = 122.0 Å. They diffract to a resolution of 4.5 Å. Two crystal forms for allosteric state R have been obtained, with hexagonal and cubic symmetries. Hexagonal crystals, which diffract to a resolution of 3.4 Å, belong to the space group P63 with unit-cell parameters a = b = 140.8, c = 145.6 Å. The cubic crystals belong to space group I23, with unit-cell parameter a = 134.32 Å and diffract to a resolution better than 2.5 Å. In all crystal forms, the dodecamer exhibits a 23 point-group symmetry.

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