V,,,, and K,,, values with twenty-five “atypical” and thirty-seven “usual” cholinesterase human sera were determined for the cholinesterase substrates procaine, tetracaine, benzoylcholine, o-nitrophenylbutyrate, cu-naphthylacetate and aspirin. Aspirin was demonstrated to be a substrate for serum cholinesterase. For each of these substrates the ratio of V,,substrate to V,,,, benzoylcholine was f...

The effect of the long chain keto acid, which is one of the secondary products from oxidative deteriolation of lipids, on the enzyme activity was investigated in vitro. Cholinesterase and succinate dehydrogenase were inhibited more effectively by 12-keto oleic acid than by linoleic acid, whereas the inhibition of trypsin by linoleic acid was greater than that caused by 12-keto oleic acid. This ...

Vasicine (VAS), a potential natural cholinesterase inhibitor, exhibited promising anticholinesterase activity in preclinical models and has been in development for treatment of Alzheimer's disease. This study systematically investigated the in vitro and in vivo metabolism of VAS in rat using ultra performance liquid chromatography combined with electrospray ionization quadrupole time-of-flight ...

The mechanism of enzyme-inhibitor-substrate reactions has been analyzed from a theoretical standpoint and illustrated by data from the system cholinesterase-physostigmine-acetylcholine. This treatment is by no means limited to a single system but should be generally applicable to others of similar type. Competitive enzyme-inhibitor-substrate systems show the same characteristic "zones of behavi...

Carbaryl is a carbamate insecticide. Like all members of this chemical family, it inhibits the action of an enzyme that is an essential component of insect, fish, bird, and mammal nervous systems. The enzyme, acetyl cholinesterase (AChE), controls the chemical reaction that transforms acetylcholine into choline after acetylcholine has been used to transmit nerve impulses across the junctions be...

A South African Afrikaans speaking family is reported in which a new high activity plasma cholinesterase variant was found to occur in the mother and son. The variant has the same electrophoretic mobility as the "usual' enzyme, but greater heat stability. Its higher specific activity is associated with a normal number of enzyme molecules. The variant may be inherited as a dominant trait, though...

Inhibitory postsynaptic currents (IPSCs) recorded at cholinergic synapses between identified neurons of the buccal ganglia of Aplysia decay exponentially. IPSC decay has been ascribed to a receptor-channel-dependent kinetic process, rather than to changes in subsynaptic acetylcholine (ACh) concentration, but is prolonged by the anticholinesterase eserine. Our data are consistent with a direct e...

Inhibitory activity of thirty-one ethanol extracts obtained from albedo, flavedo, seed and leaf parts of 17 cultivars of Citrus species from Turkey, the bark and leaves of Olea europaea L. from two locations (Turkey and Cyprus) as well as caffeic acid and hesperidin was tested against acetylcholinesterase (AChE) and butyrylcholinesterase (BChE), related to the pathogenesis of Alzheimer's diseas...

The present study was carried out to investigate the effect of benazepril on corneal permeation in goat cornea and its effect on experimentally induced acute and chronic glaucoma in rabbits. Acute glaucoma was produced by i.v. infusion of 5% glucose (15 mL/kg) in rabbits, whereas chronic glaucoma was induced by injection of alpha-chymotrypsin into posterior chamber of rabbit eye. We studied the...

Plasma cholinesterase and erythrocyte acetylcholinesterase activities have a long history of use in monitoring both workers at risk of organophosphorus pesticide (OP) exposure and in investigating accidental exposures to OPs. On account of wide inter-individual variation, the establishment of unexposed, baseline enzyme activities is necessary for accurate interpretation. This paper describes th...