Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
2007-1-9
pubmed:abstractText
A kinetically homogeneous anti-phosphate catalytic antibody preparation was shown to catalyse the hydrolysis of a series of O-aryl N-methyl carbamates containing various substituents in the 4-position of the O-phenyl group. The specific nature of the antibody catalysis was demonstrated by the adherence of these reactions to the Michaelis-Menten equation, the complete inhibition by a hapten analogue, and the failure of the antibody to catalyse the hydrolysis of the 2-nitrophenyl analogue of the 4-nitrophenylcarbamate substrate. Hammett sigma-rho analysis suggests that both the non-catalysed and antibody-catalysed reactions proceed by mechanisms in which development of the aryloxyanion of the leaving group is well advanced in the transition state of the rate-determining step. This is probably the ElcB (elimination-addition) mechanism for the non-catalysed reaction, but for the antibody-catalysed reaction might be either ElcB or B(Ac)2 (addition-elimination), in which the elimination of the aryloxy group from the tetrahedral intermediate has become rate-determining. This result provides evidence of the dominance of recognition of phenolate ion character in the phosphate hapten in the elicitation process, and is discussed in connection with data from the literature that suggest a B(Ac)2 mechanism, with rate-determining formation of the tetrahedral intermediate for the hydrolysis of carbamate substrates catalysed by an antibody elicited by a phosphonamidate hapten in which phenolate anion character is minimized. The present paper contributes to the growing awareness that small differences in the structure of haptens can produce large differences in catalytic characteristics.
pubmed:commentsCorrections
http://linkedlifedata.com/resource/pubmed/commentcorrection/17020536-10657247, http://linkedlifedata.com/resource/pubmed/commentcorrection/17020536-10722164, http://linkedlifedata.com/resource/pubmed/commentcorrection/17020536-10887904, http://linkedlifedata.com/resource/pubmed/commentcorrection/17020536-10966475, http://linkedlifedata.com/resource/pubmed/commentcorrection/17020536-11384190, http://linkedlifedata.com/resource/pubmed/commentcorrection/17020536-12379356, http://linkedlifedata.com/resource/pubmed/commentcorrection/17020536-12946271, http://linkedlifedata.com/resource/pubmed/commentcorrection/17020536-15053743, http://linkedlifedata.com/resource/pubmed/commentcorrection/17020536-1953683, http://linkedlifedata.com/resource/pubmed/commentcorrection/17020536-7809611, http://linkedlifedata.com/resource/pubmed/commentcorrection/17020536-8508792, http://linkedlifedata.com/resource/pubmed/commentcorrection/17020536-9337880
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
1470-8728
pubmed:author
pubmed:issnType
Electronic
pubmed:day
1
pubmed:volume
401
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
721-6
pubmed:dateRevised
2010-9-16
pubmed:meshHeading
pubmed:year
2007
pubmed:articleTitle
Evidence that the mechanism of antibody-catalysed hydrolysis of arylcarbamates can be determined by the structure of the immunogen used to elicit the catalytic antibody.
pubmed:affiliation
School of Pharmacy and Biomolecular Sciences, University of Brighton, Cockcroft Building, Lewes Road, Moulsecoomb, Brighton BN2 4GJ, UK.
pubmed:publicationType
Journal Article