消化
中文名称
通路描述
饮食中的碳水化合物、脂肪和蛋白质必须被分解为它们的组成单糖、脂肪酸和固醇，以及氨基酸，才能在小肠中被吸收。
饮食中的长链甘油三酯和胆固醇酯在胃和小肠中被水解，产生长链脂肪酸、单酰甘油、甘油和胆固醇，通过多种脂肪酶的作用，然后被吸收进入肠上皮细胞。
碳水化合物包括淀粉（淀粉链和支链淀粉）和双糖，如蔗糖、乳糖、麦芽糖，以及少量赤藓糖。淀粉的消化始于唾液和小肠中分泌的淀粉酶的作用，将其转化为麦芽三糖、麦芽糖、极限糊精和少量的葡萄糖。极限糊精和双糖（饮食来源和淀粉来源）的消化，将双糖分解为单糖——葡萄糖、半乳糖和果糖——是由位于小肠绒毛微绒毛上肠上皮细胞表面的酶完成的。
饮食蛋白质被胃中的胃蛋白酶和肠内一系列水解酶水解为二肽和氨基酸。所有这些酶都以无活性（前酶）形式释放，并在胃肠道腔内通过肽酶切割激活（Van Beers et al. 1995; Yamada 2015）。
饮食中的长链甘油三酯和胆固醇酯在胃和小肠中被水解，产生长链脂肪酸、单酰甘油、甘油和胆固醇，通过多种脂肪酶的作用，然后被吸收进入肠上皮细胞。
碳水化合物包括淀粉（淀粉链和支链淀粉）和双糖，如蔗糖、乳糖、麦芽糖，以及少量赤藓糖。淀粉的消化始于唾液和小肠中分泌的淀粉酶的作用，将其转化为麦芽三糖、麦芽糖、极限糊精和少量的葡萄糖。极限糊精和双糖（饮食来源和淀粉来源）的消化，将双糖分解为单糖——葡萄糖、半乳糖和果糖——是由位于小肠绒毛微绒毛上肠上皮细胞表面的酶完成的。
饮食蛋白质被胃中的胃蛋白酶和肠内一系列水解酶水解为二肽和氨基酸。所有这些酶都以无活性（前酶）形式释放，并在胃肠道腔内通过肽酶切割激活（Van Beers et al. 1995; Yamada 2015）。
英文描述
Digestion Dietary carbohydrates, fats, and proteins must be broken down to their constituent monosaccharides, fatty acids and sterols, and amino acids, respectively, before they can be absorbed in the intestine.
Dietary lipids such as long-chain triacylglycerols and cholesterol esters are hydrolyzed in the stomach and small intestine to yield long-chain fatty acids, monoacylglycerols, glycerol and cholesterol through the action of a variety of lipases, and are then absorbed into enterocytes.
Carbohydrates include starch (amylose and amylopectin) and disaccharides such as sucrose, lactose, maltose and, in small amounts, trehalose. The digestion of starch begins with the action of amylase enzymes secreted in the saliva and small intestine, which convert it to maltotriose, maltose, limit dextrins, and some glucose. Digestion of the limit dextrins and disaccharides, both dietary and starch-derived, to monosaccharides - glucose, galactose, and fructose - is accomplished by enzymes located on the luminal surfaces of enterocytes lining the microvilli of the small intestine.
Dietary protein is hydrolyzed to dipeptides and amino acids by the action of pepsin in the stomach and an array of intestinal hydrolases. All of these enzymes are released in inactive (proenzyme) forms and activated by proteolytic cleavage within the gastrointestinal lumen (Van Beers et al. 1995; Yamada 2015).
Dietary lipids such as long-chain triacylglycerols and cholesterol esters are hydrolyzed in the stomach and small intestine to yield long-chain fatty acids, monoacylglycerols, glycerol and cholesterol through the action of a variety of lipases, and are then absorbed into enterocytes.
Carbohydrates include starch (amylose and amylopectin) and disaccharides such as sucrose, lactose, maltose and, in small amounts, trehalose. The digestion of starch begins with the action of amylase enzymes secreted in the saliva and small intestine, which convert it to maltotriose, maltose, limit dextrins, and some glucose. Digestion of the limit dextrins and disaccharides, both dietary and starch-derived, to monosaccharides - glucose, galactose, and fructose - is accomplished by enzymes located on the luminal surfaces of enterocytes lining the microvilli of the small intestine.
Dietary protein is hydrolyzed to dipeptides and amino acids by the action of pepsin in the stomach and an array of intestinal hydrolases. All of these enzymes are released in inactive (proenzyme) forms and activated by proteolytic cleavage within the gastrointestinal lumen (Van Beers et al. 1995; Yamada 2015).
所含基因
5 个基因