Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.16.2 (PCP)
 3,761 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A new receptor based assay is described for the determination of classes of drugs which have high affinities for the acetylcholine receptor. The method is based upon the inhibition of the enzyme activity of an enzyme-drug conjugate by the binding to the receptor protein, and competition between free drugs and the enzyme-drug conjugate for a limited number of receptor sites. The activity of the enzyme marker system, glucose-6-phosphate dehydrogenase covalently conjugated to desipramine, is monitored by colorimetric detection of the rate of NADH formation at 340 nM. The procedure proposed is designed to provide a simple drug screen which can be done in a minimally equipped laboratory while achieving the required sensitivity. The technique is illustrated for three acetylcholine channel binding compounds: the hallucinogen phencyclidine (PCP) and the antipsychotic agents chlorpromazine and trifluoperazine. This procedure yields calibration curves with detection limits at nanomolar levels of drug, with binding responses dependent on the amounts of receptor and enzyme-labeled drug used. Aspecific binding responses of unlabeled enzyme to drug or receptor to compounds with low affinity for the receptor are shown to have minimal effect on the assay.
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PMID:Enzyme-amplified receptor assay screening test for chlorpromazine, trifluoperazine, and phencyclidine. 169 Feb 78

To drug-free urine specimens, we added the following drugs of abuse to give concentrations twice the cutoff value for positive test results: 11-nor-9-carboxy-delta-9-tetrahydrocannabinol (9-carboxy-THC), oxazepam, secobarbital, morphine, benzoylecgonine, amphetamine, or phencyclidine (PCP). Visine was then added. Although measured concentrations of several drugs were decreased in the presence of Visine, false-negative results were obtained only for 9-carboxy-THC for the EMIT-d.a.u. and TDx urine cannabinoid assays. Visine also decreased 9-carboxy-THC as measured by the Abuscreen assay. At low concentrations of Visine, false-negative cannabinoid results were attributable to the benzalkonium chloride ingredient of Visine. The added Visine was not detectable by routine urine analysis and had no effect on the activity of the glucose-6-phosphate dehydrogenase-drug conjugate used in the EMIT-d.a.u. assays. Moreover, analysis by gas chromatography/mass spectrometry showed no chemical modification or loss of 9-carboxy-THC in the Visine-adulterated urine specimens. However, Visine did increase the adhesion of 9-carboxy-THC to the borosilicate glass specimen containers. Results of ultrafiltration studies with Visine suggest that 9-carboxy-THC partitions between the aqueous solvent and the hydrophobic interior of benzalkonium chloride micelles, thereby reducing the availability of 9-carboxy-THC in antibody-based assays.
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PMID:Mechanism of false-negative urine cannabinoid immunoassay screens by Visine eyedrops. 246 64

Permeable spheroplasts were prepared from two strains of Saccharomyces cerevisiae by incubating with zymolyase without a permeabilizing agent. The loss of the plasma membrane barrier was confirmed by the nucleotide release, the activity of glucose 6-phosphate dehydrogenase with external substrates and by the effects on respiration of mitochondrial substrates and ADP. Mitochondrial integrity was maintained, as shown by respiration with lactate, pyruvate, glucose and ethanol, and its acceleration by ADP showed a coupled respiration. Potassium uptake into the vacuole was measured with a selective electrode and found to be taken up effectively by spheroplasts only in the presence of Mg-ATP; it was reverted by CCCP and PCP and inhibited by bafilomycin A1, but not by sodium vanadate or sodium azide. Potassium ions did not alter DeltaPsi of the vacuole, followed with oxonol V, but caused vacuolar alkalinization, as followed with pyranine. The increase of vacuolar pH was non-selective and observed at 50-200 mM of several monovalent cations. Isolated vacuoles with pyranine inside showed similar changes of the internal pH in the presence of KCl. Results indicate that some strains do not require a permeabilizing agent to directly access the vacuole in spheroplasts prepared with zymolyase. The hypothesis about the existence of a K+/H+ antiporter in the vacuolar membrane of S. cerevisiae is discussed.
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PMID:In situ study of K+ transport into the vacuole of Saccharomyces cerevisiae. 1603 2