Chelminska-Bertilsson M, Edebo A, Thompson R A, Edebo L
Dept. of Clinical Bacteriology, Göteborg University, Sweden.
Scand J Gastroenterol. 1995 Jul;30(7):670-4. doi: 10.3109/00365529509096311.
The hydrolysis of long-chain alkanoylcholines, presumably catalyzed by butyryl-cholinesterase (EC 3.1.1.8), in rat intestinal loops was studied. The substances have earlier been found to be rapidly degraded in vitro.
Radiolabeled substrates were used, and a radiochromatographic detection method was applied.
The long-chain alkanoylcholines were rapidly hydrolyzed. The rates of the reaction and the chain-length dependence were similar to those reported earlier in vitro. At high substrate concentrations the hydrolysis reaction was inhibited. This could be due to conformational changes of the enzyme, caused by the adsorption of the cationic amphiphile, or to a decrease in the free substrate concentration after incorporation of the amphiphilic ester into the lipid layer of the cell membranes. The enzymatic activity towards the substrates in different parts of the rat intestinal tract was also studied and found to be highest in the duodenum.
研究了大鼠肠袢中长链烷酰胆碱的水解反应，推测该反应由丁酰胆碱酯酶（EC 3.1.1.8）催化。此前已发现这些物质在体外会迅速降解。
使用放射性标记的底物，并应用放射色谱检测方法。
长链烷酰胆碱迅速水解。反应速率和链长依赖性与之前体外研究报道的相似。在高底物浓度下，水解反应受到抑制。这可能是由于阳离子两亲物吸附导致酶的构象变化，或者是两亲性酯掺入细胞膜脂质层后游离底物浓度降低所致。还研究了大鼠肠道不同部位对底物的酶活性，发现十二指肠中的活性最高。
