Friedrich M, Noack J, Proll J, Noack R
Biomed Biochim Acta. 1984;43(1):117-30.
Casein, wheat gluten or field-bean protein isolate (vicia faba) was hydrolyzed enzymatically by trypsin or thermitase (proteinase from Thermoactinomyces vulgaris). The degree of splitting of the protein peptide bounds was, resp., 18% or 30% for casein, 8% or 30% for wheat gluten and 16% or 29% for the field-bean protein isolate. The peptide pattern of the protein hydrolysates was measured by gel chromatography. The absorption of the enzymatic protein hydrolysates was compared with the absorption of the equimolar mixtures of free amino acids by perfusion of the distal or proximal part of the small intestine of nonanaesthesized rats. The absorption was measured on the basis of the amino acid disappearance from the perfused part of the small intestine and expressed as absorption of the total amino acids, of each single amino acid and as coefficient of variation of amino acid absorption. There are no differences in the total amino acid absorption of the tryptic casein hydrolysate and the three thermitatic protein hydrolysates compared with their corresponding mixtures of free amino acids. The absorption is decreased in case of larger oligopeptides. Their preceding mucosal hydrolysis is slower than the absorption of the splitting products. This is true for tryptic hydrolysates of wheat gluten and field-bean protein. The absorption patterns of the single amino acids are different for protein hydrolysates compared with their equimolar mixtures of amino acids in case of a same total absorption, too. The coefficient of variation is low (more equal amino acid absorption) in hydrolysates consisting of a homogeneous mixture of low molecular weight peptides. It is more increased in mixtures of free amino acids or in hydrolysates containing longer-chain peptides.
酪蛋白、小麦面筋或蚕豆分离蛋白（蚕豆）用胰蛋白酶或嗜热菌蛋白酶（来自普通嗜热放线菌的蛋白酶）进行酶解。蛋白质肽键的裂解程度，酪蛋白分别为18%或30%，小麦面筋为8%或30%，蚕豆分离蛋白为16%或29%。通过凝胶色谱法测定蛋白质水解产物的肽谱。通过对未麻醉大鼠小肠远端或近端进行灌注，将酶解蛋白质水解产物的吸收与等摩尔游离氨基酸混合物的吸收进行比较。根据小肠灌注部分氨基酸的消失情况来测量吸收，并表示为总氨基酸的吸收、每种单个氨基酸的吸收以及氨基酸吸收的变异系数。与相应的游离氨基酸混合物相比，胰蛋白酶解酪蛋白水解产物和三种嗜热菌蛋白酶解蛋白质水解产物的总氨基酸吸收没有差异。对于较大的寡肽，吸收会降低。它们先前的黏膜水解比裂解产物的吸收慢。小麦面筋和蚕豆蛋白的胰蛋白酶水解产物就是如此。在总吸收相同的情况下，蛋白质水解产物中单个氨基酸的吸收模式与它们等摩尔氨基酸混合物的吸收模式也不同。由低分子量肽的均匀混合物组成的水解产物中变异系数较低（氨基酸吸收更均匀）。在游离氨基酸混合物或含有较长链肽的水解产物中，变异系数会增加得更多。
