Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.1.8 (cholinesterase)
 12,691 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Various carbamic acid esters (CAE) of a new class of dopaminergic drugs, 5-substituted 8-chloro-7-hydroxy-3-methyl-2,3,4,5- tetrahydro-1 H-3-benzazepines, were synthesized and evaluated as prodrug forms with the aim of protecting the parent phenols against first-pass metabolism following oral administration. Monosubstituted CAE were found to be highly unstable at pH 7.4 and 37 degrees C, the half-lives of hydrolysis being between 4 and 40 min. Plasma from various species catalyzed the hydrolysis of the carbamates. N,N-Disubstituted carbamates, on the other hand, were stable both in buffer and plasma solutions. They showed a very potent inhibition of butyrylcholinesterase (EC 3.1.1.8), but were less potent inhibitors of the specific erythrocyte acetylcholinesterase (EC 3.1.1.17). In vitro incubations of an N,N-dimethylsubstituted carbamate ester (10) with liver microsomes from mouse and rat showed an appreciable formation of the parent phenolic compound. This bioconversion is suggested to occur via an initial cytochrome P-450-catalyzed hydroxylation to give an N-hydroxymethyl derivative which spontaneously decomposes to the N-monomethylcarbamate. It is concluded that N,N-disubstituted carbamate esters may be potentially useful prodrugs for the 7-hydroxy-3-benzazepines, whereas N-monosubstituted carbamates appear to be too chemically and enzymatically labile.
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PMID:Carbamate ester prodrugs of dopaminergic compounds: synthesis, stability, and bioconversion. 168 64

An amperometric flow-injection choline biosensor was assembled utilizing natural chitinous membrane as the supporting material for biocatalyst immobilization, and the membrane was purified from Taiwanese soldier crab, Mictyris brevidactylus. The chitinous membrane (<50.0 microm in thickness) was covalently immobilized with choline oxidase (EC 3.1.1.17 from Alcaligenes sp.) and then attached onto the platinum electrode of an amperometric flow cell. The flow cell served as the choline sensing device of the proposed FIA system. The sensor signal (peak height of the FIAgram) was linearly related to choline concentration (r=0.999 for choline up to 5.0mM) with low detection limit (S/N>3 for 10.0 microM choline) and high reproducibility (CV<3% for 1.0mM choline, n=7). The system was proved to be useful in measuring cholinesterase inhibitory activities of synthetic chemicals or natural products.
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PMID:Choline biosensor constructed with chitinous membrane from soldier crab and its application in measuring cholinesterase inhibitory activities. 1732 59

Salvinorin A is the main active psychoactive ingredient in Salvia divinorum, a Mexican plant that has been widely available as a hallucinogen in recent years. The aims of this study were to investigate the stability of salvinorin A in rat plasma, esterases responsible for its degradation, and estimation of the degradation products. The apparent first-order rate constants of salvinorin A at 37 degrees C, 25 degrees C, and 4 degrees C were 3.8 x 10(-1), 1.1 x 10(-1), and < 6.0 x 10(-3) h(-1), respectively. Salvinorin A degradation was markedly inhibited by the addition of sodium fluoride, an esterase inhibitor. Moreover, phenylmethylsulfonyl fluoride (serine esterase inhibitor) and bis-p-nitrophenylphosphate (carboxylesterase inhibitor) also inhibited salvinorin A degradation. In contrast, little or no suppression of the degradation was seen with 5,5'-dithiobis-2-nitrobenzoic acid (arylesterase inhibitor),ethopropazine (butyrylcholinesterase inhibitor), and BW284c51 (acetylcholineseterase inhibitor). These findings indicated that carboxylesterase was mainly involved in the salvinorin A hydrolysis in rat plasma.4. The degradation products of salvinorin A estimated by liquid chromatography-mass spectrometry included the deacetylated form (salvinorin B) and the lactone-ring-open forms of salvinorin A and salvinorin B. This lactone-ring-opening reactions were involved in calcium-dependent lactonase.
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PMID:In vitro stability and metabolism of salvinorin A in rat plasma. 1928 Mar 83