carbon nanotubes are regarded as promising building blocks for the construction of novel biosensors due to their unique properties like fast electron transfer, high electrocatalytic effect and good biocompatibility. in the present study, the effect of different chemical oxidation’s methods of multi-walled carbon nanotubes (mwcnts) on the electrochemical behavior of modified graphite electrodes ...

This study concerns the distribution of cholinesterases in human skin. Previous work on this subject was published last year by Hurley, Shelley and Koelle (1) These authors used a method originated by Koelle (2, 3). In Koelle's method, acetyithiocholine and butyryithiocholine are used as substrates. It is assumed that acetyithiocholine is split by specific acetyicholinesterase as well as by non...

An acetylcholinesterase (AChE) based amperometric bioelectrode for a selective detection of low concentrations of organophosphorus pesticides has been developed. The amperometric needle type bioelectrode consists of a bare cavity in a PTFE isolated Pt-Ir wire, where the AChE was entrapped into a photopolymerised polymer of polyvinyl alcohol bearing styrylpyridinium groups (PVA-SbQ). Cyclic volt...

Acetylcholinesterase is present in human red cells but cannot be demonstrated by the copper thiocholine test. The enzyme is revealed, however, in the perinuclear cisterna, endoplasmic reticulum and Golgi apparatus of red cell precursors. It is suggested that 2 forms of the enzyme are present, one of which can be demonstrated by the copper thiocholine test, the other cannot; one form may be the ...

Vapor-phase detection of the model organophosphate (OP) malathion was achieved using enzymes encapsulated in peptide nanotubes and attached to gold screen printed electrodes. The peptide nanotubes had horseradish peroxidase (HRP) encapsulated inside and both acetylthiocholine (ASCh) and acetylcholinesterase (AChE) coated on the outside. ASCh hydrolysis, which produces thiocholine, was catalyzed...

The choline esters potentiated the choline-catalysed decarbamoylation of dimethylcarbamoyl-acetylcholinesterase in proportion to the length of acyl group, although esters containing an acyl chain longer than the hexanoyl group exhibited a corresponding decrease in the potentiation. In structural requirement analysis it was found that both the quaternary ammonium moiety and the ester bond were i...

Kinetics and mechanism of hydrolysis of acetylthiocholine by the enzyme butyrylcholine esterase was studied. The spectrophotometric Ellman's method and potentiometric pH-stat method were used for continuous determination of the actual concentration of the products thiocholine and acetic acid in the reaction mixture. The validity of the Michaelis-Menten (Briggs-Haldane) equation in the whole cou...

Based on the fluorescence quenching of novel denatured protein-protected gold nanoclusters, a label-free detection method of acetylcholinesterase (AChE) activity has been developed. Using denatured bovine serum albumin (dBSA), in which 35 cysteine residues can interact polyvalently with Au nanoclusters (AuNCs) as a stabilizing agent, water-soluble and stable fluorescent gold nanoclusters were s...