Institute of Chemical Sciences and Engineering, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland.
Protein Eng Des Sel. 2013 Jan;26(1):81-9. doi: 10.1093/protein/gzs085. Epub 2012 Oct 24.
The oral delivery of protein and peptide drugs is limited by their proteolytic degradation and the poor absorption across the intestinal epithelia. In this work, we exposed a phage library of small bicyclic peptides (<1.5 kDa) to a pancreatic extract of proteases prior to affinity selection to enrich binders with higher stability in the intestinal environment. Panning with the therapeutic target plasma kallikrein yielded potent inhibitors (K(i)s between 5.6 and 336 nM) wherein bicyclic peptides isolated with proteolytic pressure were more stable. A proline residue found in a specific position of several resistant bicyclic peptides proved to be a 'protective mark', rendering the bicyclic peptides resistant to significantly higher concentrations of intestinal proteases while retaining essentially their inhibitory activity.
蛋白质和肽类药物的口服给药受到其在胃肠道上皮细胞中被蛋白水解降解以及吸收较差的限制。在这项工作中，我们在亲和选择之前，将小双环肽（<1.5 kDa）的噬菌体文库暴露于蛋白酶的胰腺提取物中，以富集在肠道环境中具有更高稳定性的结合物。用治疗靶标血浆激肽释放酶进行淘选得到了强效抑制剂（Ki 值在 5.6 和 336 nM 之间），其中在蛋白酶压力下分离的双环肽更稳定。在几个具有抗性的双环肽的特定位置发现的脯氨酸残基被证明是一个“保护标记”，使双环肽能够抵抗更高浓度的肠道蛋白酶，同时基本保持其抑制活性。
