Showing papers in "British journal of pharmacology and chemotherapy in 1947"

The affinity of atropine-like esters for esterases.

Abstract: In a recent paper from this department observations on a number of esters with atropine-like actions were reported (Ing, Dawes, and Wajda, 1945). The substances studied included the choline esters of benzilic, tropic, and atrolactinic acid, as well as esters of benzilic acid in which choline was replaced by other basic alcohols. In the experiments to be described we have investigated the behaviour of these substances towards esterases, and in particular their affinity for the cholinesterases, by testing whether or not they inhibited the hydrolysis of esters known to be substrates of these enzymes. In addition, we have examined two other esters of interest to the pharmacologist: (a) cocaine, and (b) the diethylaminoethyl ester of cyclohexyl-phenylacetic acid (trasentin 6H). Mammalian tissues contain a number of different enzymes which will hydrolyse acetylcholine and other choline esters (Alles and Hawes, 1940; Richter and Croft, 1942 Mendel and Rudney, 1943; Zeller and Bissegger, 1943; Nachmansohn and Rothenberg, 1945). Mendel and Rudney have shown that two different types of cholinesterase can be characterized by using acetylcholine and benzoylcholine as substrates; they distinguish the \"true\" cholinesterase from the \"pseudo \"-cholinesterase. The former will hydrolyse acetylcholine only, the latter both acetylcholine and benzoylcholine. We have found Mendel's nomenclature useful in describing our results and it has therefore been employed in this paper. In addition to these two types of enzymes, preparations have been described which will hydrolyse benzoylcholine, but not acetylcholine. The guinea-pig liver (Sawyer, 1945) and the ox kidney (Gunter, 1946) each contain an enzyme of this kind. %