Department of Chemistry, University of Tromsø, N-9037 Tromsø, Norway.
J Med Chem. 2012 Jul 26;55(14):6294-305. doi: 10.1021/jm3002058. Epub 2012 Jul 11.
This study investigates how the S1 and S3 site of trypsin can be challenged with cationic amino acid analogues to yield active antimicrobial peptides with stability toward tryptic degradation. It is shown that unnatural analogues can be incorporated to generate stable peptides with maintained bioactivity to allow for a potential oral uptake. Selected peptides were studied using isothermal calorimetry and computational methods. Both stable and unstable peptides were found to bind stoichiometrically to trypsin with dissociation constants ranging 2-60 μM, suggesting several different binding modes. The stability of selected peptides was analyzed in whole organ extracts and the incorporation of homoarginine and 2-amino-(3-guanidino)propanoic acid resulted in a 14- and 50-fold increase in duodenal stability. In addition, a 40- and 70-fold increase in stomach stability is also reported. Overall, these results illustrate how the incorporation of cationic side chains can be employed to generate bioactive peptides with significant systemic stability.
本研究探讨了如何用阳离子氨基酸类似物挑战胰蛋白酶的 S1 和 S3 位点，从而产生具有抗胰酶降解稳定性的活性抗菌肽。结果表明，可引入非天然类似物来生成具有保持生物活性的稳定肽，从而允许潜在的口服摄取。使用等温热法和计算方法研究了选定的肽。发现稳定和不稳定的肽都与胰蛋白酶以化学计量比结合，解离常数范围为 2-60 μM，表明存在几种不同的结合模式。在整个器官提取物中分析了选定肽的稳定性，并发现精氨酸和 2-氨基-(3-胍基)丙酸的掺入使十二指肠稳定性分别增加了 14 倍和 50 倍。此外，还报道了胃稳定性分别增加了 40 倍和 70 倍。总体而言，这些结果说明了如何利用阳离子侧链的引入来生成具有显著系统稳定性的生物活性肽。
