Effect of barley endoprotease EP-B2 on gluten digestion in the intact rat
Effect of barley endoprotease EP-B2 on gluten digestion in the intact rat
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DOI：
10.1124/jpet.106.104315
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发表时间：
2006-09-01
影响因子：
3.5
通讯作者：
Khosla, Chaitan
中科院分区：
文献类型：
--
作者：
Gass, Jonathan;Vora, Harmit;Khosla, Chaitan
乳糜泻是一种多因素疾病，其特征是肠道对摄入麸质的炎症反应。来自小麦、黑麦和大麦的抗蛋白水解谷蛋白肽在肠腔中持续存在，并在遗传易感个体中引起免疫应答。在这里，我们证明了在体内的面筋消化蛋白酶（“麦谷蛋白酶”）的能力，以加速富含面筋的固体粉的分解。将内切蛋白酶B的酶原形式，即来自大麦（Hordeum vulgare）的同种型2（EP-B2），与含有1 g谷蛋白的固体膳食一起口服给药于成年大鼠。通过高效液相色谱法和质谱法监测胃和小肠中谷蛋白的消化作为酶剂量和时间的函数。在没有补充EP-B2的情况下，面筋在胃中溶解和蛋白水解到有限的程度，并且主要在小肠中水解和同化。相比之下，EP-B2在大鼠胃中以剂量和时间依赖性方式消化麸质方面非常有效。在1：25的EP-B2/谷蛋白剂量下，高免疫原性33聚体麦胶蛋白肽的胃浓度在90分钟内降低了50倍以上，没有明显的毒性迹象。因此，评价EP-B2作为饮食控制的辅助手段在乳糜泻患者中是必要的。
Celiac Sprue is a multifactorial disease characterized by an intestinal inflammatory response to ingested gluten. Proteolytically resistant gluten peptides from wheat, rye, and barley persist in the intestinal lumen and elicit an immune response in genetically susceptible individuals. Here, we demonstrate the in vivo ability of a gluten-digesting protease ("glutenase") to accelerate the breakdown of a gluten-rich solid meal. The proenzyme form of endoprotease B, isoform 2 from Hordeum vulgare ( EP-B2), was orally administered to adult rats with a solid meal containing 1 g of gluten. Gluten digestion in the stomach and small intestine was monitored as a function of enzyme dose and time by high-performance liquid chromatography and mass spectrometry. In the absence of supplementary EP-B2, gluten was solubilized and proteolyzed to a limited extent in the stomach and was hydrolyzed and assimilated mostly in the small intestine. In contrast, EP-B2 was remarkably effective at digesting gluten in the rat stomach in a dose- and time-dependent fashion. At a 1:25 EP-B2/gluten dose, the gastric concentration of the highly immunogenic 33-mer gliadin peptide was reduced by more than 50-fold within 90 min with no overt signs of toxicity. Evaluation of EP-B2 as an adjunct to diet control is therefore warranted in celiac patients.