Fatty acid acylation of mucin by gastric mucosa: effects of sofalcone and sucralfate.
Fatty acid acylation of mucin by gastric mucosa: effects of sofalcone and sucralfate.
复制标题
胃粘膜对粘蛋白的脂肪酸酰化：索法酮和硫糖铝的作用。
DOI：
10.1016/0006-2952(87)90644-7
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发表时间：
1987
影响因子：
5.8
通讯作者：
Slomiany,A
中科院分区：
文献类型：
--
作者：
Slomiany,BL;Liau,YH;Mizuta,K;Slomiany,A
研究了抗溃疡药物索法酮和硫糖铝对胃粘膜糖蛋白脂肪酰基转移酶活性的影响。将大鼠胃粘膜微粒体洗涤剂提取物中含有的酰基转移酶与脱酰化的胃粘蛋白和棕榈酰辅酶A底物在有无药物存在下孵育，并对形成的脂肪酸酰化糖蛋白产物进行定量。在无药物存在的情况下，随着底物浓度和酶浓度的增加，酶活呈正比增加，Km值为5.6×10−7M。在反应混合物中引入软脂酮可以提高粘液糖蛋白的酰化速率。在1.0×10−5M范围内，增强率与软脂酮浓度成正比，Km值为3.7×10−7M。硫糖铝抑制了酰基转移酶的活性，与索法酮相反。硫糖铝对粘液糖蛋白酰化的抑制率为竞争性，在1.0×10−4M时达到25%。由硫糖铝双倒数作图计算的表观KI值为9.1×10−7M。由于粘蛋白与脂肪酸的酰化作用在维持胃粘膜完整性中起着重要作用，结果提示软脂酮对脂肪酰基转移酶的刺激可能是该药促进溃疡愈合的有益作用之一。
The effects of antiulcer drugs, sofalcone and sucralfate, on the activity of gastric mucosal mucus glycoprotein fatty acyltransferase were investigated. The acyltransferase enzyme, contained in the detergent extracts of the microsomal fraction of rat gastric mucosa, was incubated with the deacylated gastric mucin and palmitoyl-CoA substrates in the presence and absence of drugs, and the formed fatty acid acylated glycoprotein product was quantitated. In the absence of drugs, the enzymatic activity increased proportionally with increased concentrations of both substrates and of enzyme, and gave an apparentKmvalue of 5.6 × 10−7M. Introduction of sofalcone to the reaction mixtures led to an enhancement in the rate of mucus glycoprotein acylation. The rate of enhancement was proportional to sofalcone concentration up to 1.0 × 10−5M, with an apparantKmvalue of 3.7 × 10−7M. In contrast to sofalcone, the acyltransferase activity was inhibited by sucralfate. The rate of inhibition of mucus glycoprotein acylation by sucralfate was of the competitive type and at 1.0 × 10−4M reached a value of 25%. The apparentKIvalue calculated from the double-reciprocal plots for sucralfate was 9.1 × 10−7M. As the acylation of mucin with fatty acids plays an important role in the maintenance of gastric mucosal integrity, the results suggest that stimulation of the fatty acyltransferase enzyme by sofalcone may be one of the beneficial effects of this drug towards ulcer healing.