Alginate as a protease inhibitor in vitro and in a model gut system; selective inhibition of pepsin but not trypsin.
Alginate as a protease inhibitor in vitro and in a model gut system; selective inhibition of pepsin but not trypsin.
复制标题
DOI：
10.1016/j.carbpol.2015.05.062
复制
发表时间：
2015-10-20
影响因子：
11.2
通讯作者：
Pearson JP
中科院分区：
文献类型：
--
作者：
Chater PI;Wilcox MD;Brownlee IA;Pearson JP
海藻酸盐抑制胃酶的蛋白分解活性，但不抑制胰蛋白酶。胃酶抑制程度与藻酸盐F[M]相关。采用体外模拟肠道系统模拟海藻酸盐对蛋白质降解的抑制作用。蛋白质分解在胃期受到抑制，但在小肠阶段不受抑制。在pH为2.5时，依赖于pH的离子相互作用会降低底物的利用率。海藻酸盐被广泛用于食品和医疗行业，包括作为胃食道反流的治疗。本工作研究了海藻酸盐对反流侵袭者胰蛋白酶和胃酶的抑制作用，以及海藻酸盐与底物的结合、pH和海藻酸盐结构对抑制作用的影响。海藻酸盐在体外可使胃酶活性降低53.9%(±9.5SD)。海藻酸甘露酸脂残留频率与胃酶抑制水平呈显著正相关。对胰酶的抑制作用有限。对藻酸盐和蛋白质之间依赖于pH的相互作用的粘度学观察表明，在酸性pH下，依赖于pH的离子相互作用降低了底物对酶的利用率。为了了解海藻酸盐对饲料蛋白质消化的影响，在体外上消化道模型中进行了蛋白质分解消化的研究。在消化的胃期，蛋白质的降解受到显著的抑制，而在小肠阶段则不明显。
Alginate inhibits proteolytic activity of pepsin but not trypsin. Level of pepsin inhibition correlates with alginate F[M]. An in vitro model gut system was used to model alginate inhibition of proteolysis. Proteolysis inhibited in gastric phase of digestion, but not small intestinal phase. pH dependent ionic interactions reduce substrate availability at pH 2.5. Alginates are widely used in the food and medical industries, including as a Gastro-Oesophagul Reflux treatment. This work investigates the inhibitory effects of alginate on the reflux aggressors trypsin and pepsin and the role of alginate-substrate binding, pH and alginate structure on inhibition. Alginates were shown to reduce pepsin activity by up to 53.9% (±9.5SD) in vitro. Strong positive correlation between alginate mannuronate residue frequency and levels of pepsin inhibition was observed. Limited inhibition of trypsin was shown. Viscometric observations of pH dependent interactions between alginate and protein suggest a mechanism whereby pH dependent ionic interactions reduce substrate availability to enzyme at acidic pH. To understand how dietary protein digestion is affected by alginate, proteolytic digestion was investigated in an in vitro model of the upper digestive tract. Significant inhibition of proteolysis was shown in the gastric phase of digestion, but not the small intestinal phase.