Keyword search (4,059 papers available)


Partial purification, kinetic analysis, and amino acid sequence information of a flavonol 3-O-methyltransferase from Serratula tinctoria.

Author(s): Huang TS, Anzellotti D, Dedaldechamp F, Ibrahim RK

Plant Physiol. 2004 Apr;134(4):1366-76 Authors: Huang TS, Anzellotti D, Dedaldechamp F, Ibrahim RK

Article GUID: 15084728
Effects of surfactants on rhizodegradation of oil in a contaminated soil.

Author(s): Memarian R, Ramamurthy AS

J Environ Sci Health A Tox Hazard Subst Environ Eng. 2012;47(10):1486-90 Authors: Memarian R, Ramamurthy AS

Article GUID: 22571537
Enzymatic assay for GHB determination in forensic matrices.

Author(s): Grenier V, Huppé G, Lamarche M, Mireault P

J Anal Toxicol. 2012 Sep;36(7):523-8 Authors: Grenier V, Huppé G, Lamarche M, Mireault P

Article GUID: 22722059
Odorous gaseous emissions as influence by process condition for the forced aeration composting of pig slaughterhouse sludge.

Author(s): Blazy V, de Guardia A, Benoist JC, Daumoin M, Lemasle M, Wolbert D, Barrington S

Waste Manag. 2014 Jul;34(7):1125-38 Authors: Blazy V, de Guardia A, Benoist JC, Daumoin M, Lemasle M, Wolbert D, Barrington S

Article GUID: 24768513
Development of a particle-trap preconcentration-soft ionization mass spectrometric technique for the quantification of mercury halides in air

Author(s): Deeds DA; Ghoshdastidar A; Raofie F; Guérette ÉA; Tessier A; Ariya PA;

Measurement of oxidized mercury, Hg(II), in the atmosphere poses a significant analytical challenge as Hg(II) is present at ultra-trace concentrations (picograms per cubic meter air). Current technologies are sufficiently sensitive to measure the total Hg p...

Article GUID: 25837315
Lithocholic bile acid accumulated in yeast mitochondria orchestrates a development of an anti-aging cellular pattern by causing age-related changes in cellular proteome.

Author(s): Beach A, Richard VR, Bourque S, Boukh-Viner T, Kyryakov P, Gomez-Perez A, Arlia-Ciommo A, Feldman R, Leonov A, Piano A, Svistkova V, Titorenko VI

Cell Cycle. 2015;14(11):1643-56 Authors: Beach A, Richard VR, Bourque S, Boukh-Viner T, Kyryakov P, Gomez-Perez A, Arlia-Ciommo A, Feldman R, Leonov A, Piano A, Svistkova V, Titorenko VI

Article GUID: 25839782
Electrochemical efficacy of a carboxylated multiwalled carbon nanotube filter for the removal of ibuprofen from aqueous solutions under acidic conditions.

Author(s): Bakr AR, Rahaman MS

Chemosphere. 2016 Jun;153:508-20 Authors: Bakr AR, Rahaman MS

Article GUID: 27035389
On-chip integration of droplet microfluidics and nanostructure-initiator mass spectrometry for enzyme screening

Author(s): Joshua Heinemann

Biological assays often require expensive reagents and tedious manipulations. These shortcomings can be overcome using digitally operated microfluidic devices that require reduced sample volumes to automate assays. One particular challenge is integrating bi...

Article GUID: 27957569
Varying the rate of intravenous cocaine infusion influences the temporal dynamics of both drug and dopamine concentrations in the striatum

Author(s): Minogianis EA; Shams WM; Mabrouk OS; Wong JT; Brake WG; Kennedy RT; du Souich P; Samaha AN;...

The faster drugs of abuse reach the brain, the greater is the risk of addiction. Even small differences in the rate of drug delivery can influence outcome. Infusing cocaine intravenously over 5 vs....

Article GUID: 29757478
Title:Identification of active site residues of chorismate mutase-prephenate dehydrogenase from Escherichia coli.
Authors:Christendat D,  Turnbull J
Link:www.ncbi.nlm.nih.gov/pubmed/8605196?dopt=Abstract
DOI:10.1021/bi9525637
Category:Biochemistry
PMID:8605196
Dept Affiliation: CHEMBIOCHEM
1 Department of Chemistry and Biochemistry, Concordia University, Montreal, Quebec, Canada.

Description:

Identification of active site residues of chorismate mutase-prephenate dehydrogenase from Escherichia coli.



Biochemistry. 1996 Apr 09;35(14):4468-79



Authors: Christendat D, Turnbull J



Abstract

Chemical modification studies of the bifunctional enzyme chorismate mutase-prephenate dehydrogenase and mass spectral analysis of peptide fragments containing modified residues are presented. The reaction with diethyl pyrocarbonate (DEPC) results in the modification of several enzymic groups, including a single histidine group essential for dehydrogenase activity and a single lysine residue essential for mutase activity. This conclusion is based on the following evidence. (1) Hydroxylamine rapidly restores dehydrogenase activity to the DEPC-inactivated enzyme without restoring mutase activity. (2) Mutase activity is also lost upon treatment of the enzyme with trinitrobenzene sulfonate. (3) The reactivity of the dehydrogenase to DEPC increases with pH, suggesting the participation of a group with a pKa of 7.0 in the dehydrogenase reaction. (4) Two peptides identified by differential peptide mapping had mass values matching those calculated for peptides comprising residues 127-135 (containing His131) and residues 36-48 (containing Lys37). In support of the idea that the residues being modified are within the active sites, we show that the substrates prephenate and nicotinamide adenine dinucleotide (NAD+) offer protection against inactivation of dehydrogenase activity while inactivation of mutase activity can be prevented by prephenate and a transition state analogue (3-endo-8-exo)-8-hydroxy-2-oxabicyclo[3.3.1]-non-6-ene-3,5-dicarboxylic acid (endo-oxabicyclic diacid). Lys37 is conserved among several chorismate mutases and may participate in catalysis by interacting with an ether oxygen between C-5 and C-8 of chorismate in the transition state. His131 may be assisting in a hydride transfer from prephenate to NAD+ in the dehydrogenase reaction.



PMID: 8605196 [PubMed - indexed for MEDLINE]