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Molar absorption coefficients for the reduced Ellman reagent: reassessment.
The data show that the absorbance spectra of TNB are shifted to longer wavelengths when temperature increases, while absorbance maxima decrease, and this should be taken into account when the Ellman method is used for determination of enzyme activities, such as in cholinesterase assays. Expand
Role of the peripheral anionic site on acetylcholinesterase: inhibition by substrates and coumarin derivatives.
Evidence is presented that competition with propidium obtained by direct fluorescence titrations, when combined with inhibition kinetics, provides a more reliable means for ascertaining site selectivity of various inhibitors than does a kinetic analysis alone. Expand
Spontaneous reactivation and aging of dimethylphosphorylated acetylcholinesterase and cholinesterase
Abstract Spontaneous reactivation and aging of dimethylphosphorylated acetylcholinesterase (acetylcholine hydrolase, EC from human and bovine erythrocytes and rat brain, and cholinesteraseExpand
Acetylcholinesterase active centre and gorge conformations analysed by combinatorial mutations and enantiomeric phosphonates.
The sequence of mutations to enlarge the size of the AChE active-centre gorge did not show an ordered conversion into BChE reactivity as anticipated for a rigid template, but the individual aromatic residues may mutually interact to confer a distinctive stereospecificity pattern towards organophosphates. Expand
Interaction of some trialkyl phosphorothiolates with acetylcholinesterase. Characterization of inhibition, aging and reactivation.
The reaction of bovine erythrocyte acetylcholinesterase with a set of structurally related phosphorothiolates was studied and it was concluded that the leaving group of during phosphorylation is the S-alkyl. Expand
Differentiation of esterases reacting with organophosphorus compounds.
The hydrolysis of paraoxon (POX), phenylacetate (PA) and beta-naphthylacetate (BNA) was studied in human serum. Based upon correlations between enzyme activities, upon reversible inhibition by EDTAExpand
Acetylcholinesterase. Two types of inhibition by an organophosphorus compound: one the formation of phosphorylated enzyme and the other analogous to inhibition by substrate.
T theoretical equations were derived for an enzyme with two binding sites to both of which substrate and inhibitor can combine, and it was shown that haloxon combines with a site involved in inhibition by substrate. Expand
Mutant cholinesterases possessing enhanced capacity for reactivation of their phosphonylated conjugates.
Rates of reactivation reach values sufficient for consideration of mixtures of a mutant enzyme and an oxime as a scavenging strategy in protection and treatment of organophosphate exposure. Expand