Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.1.7 (acetylcholinesterase)
 28,390 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

From April 1978 through December 1989, a total of 17 patients with unresectable hepatocellular carcinoma (HCC) were treated with radiation therapy alone or radiation therapy in conjunction with percutaneous ethanol injection (PEI), transarterial infusion chemotherapy (TAI), or transarterial embolization (TAE) at the National Medical Center Hospital. The median survival of all patients was 13.8 months. The survival values determined at 1, 2, and 3 years were 58.8%, 26.1%, and 9.8%, respectively. Only the pretreatment liver function affected the survival value. Between patients who did not have liver cirrhosis (LC) as well as those who had LC of Child's class A and patients who had LC of Child's class B or C, the differences observed in the 1-year survival value and the median duration of survival were statistically significant (P < 0.05). The serum cholinesterase (ChE) level seemed to be a good indicator of liver function during the radiation therapy. A field size of 150 cm2 and a total dose of 5000 cGy (TDF 82) seemed to be well tolerated by patients who did not have LC and those who had LC of Child's class A. The field size determined whether patients with poor liver function such as LC of Child's class B or C would develop severe hepatic deterioration after undergoing radiation therapy.
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PMID:Radiation therapy in patients with unresectable hepatocellular carcinoma. 133 96

p-(trimethyl ammonium) benzene diazonium difluoroborate (TDF), an affinity-labeling reagent of the acetylcholine receptor site(s), which in the normal cell acts as an irreversible inhibitor becomes a reversible activator after in vivo exposure of the electroplax to dithiothreitol (DTT), a disulfide bond reducing agent. After in vitro exposure of acetylcholinesterase to DTT, TDF becomes a reversible competitive inhibitor of the enzyme, using indophenyl acetate as the substrate. Both acetylcholinesterase and the macromolecular receptor of acetylcholine thus contain disulfide bonds. Additional experiments with DTT suggest that there might exist several different classes of receptor sites for cholinergic agents in the excitable membrane of the electroplax.
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PMID:Compared effects of dithiotreitol on the interaction of an affinity-labeling reagent with acetylcholinesterase and the excitable membrane of the electroplax. 526 Sep 26

Several properties of the enzyme acetylcholinesterase (AChE) isolated in vitro are compared with those of the membrane receptor(s) of acetylcholine expressed by the in vivo electrical response of the electroplax membrane. AChE strongly binds in vitro effectors of the electroplax: agonists e.g., decamethonium or antagonists, e.g., d-tubocurarine and flaxedil. It also reacts covalently with an affinity labeling reagent of the acetylcholine receptor site(s) in vivo (TDF). Two classes of sites on AChE molecule account for the binding of these quaternary nitrogen containing compounds: (1) the anionic site of the active center and (2) noncatalytic "peripheral anionic centers" located outside the active center. A disulfide bond breaking agent, dithiothreitol (DTT) alters in a parallel manner the reaction of AChE and the excitable membrane of the electroplax to TDF. The irreversibility of TDF action is lost in both cases, after exposure to DTT. Both AChE and the acetylcholine receptor thus contain disulfide bonds-they are closely related but not necessarily identical proteins.
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PMID:On Some Structural Analogies between Acetylcholinesterase and the Macromolecular Receptor of Acetylcholine. 1987 43