Smart nanocarriers for the transport of drugs to tumor cells are nowadays of great interest for treating cancer. The use of enzymatic stimuli to cleave peptide-based drug nanocapsules for the selective release of nanocapsule cargo in close proximity to tumor cells opens new possibilities in cancer research. In the present work, we demonstrate a methodology for finding and optimizing cleavable substrate sequences by the type II transmembrane serine protease hepsin, which is highly overexpressed in prostate cancer. The design and screening of combinatorial libraries in silico against the binding cavity of hepsin allow the identification of a panel of promising substrates with high-calculated docking scores. In vitro screening verifies the predictions and showed that all substrates are cleaved by hepsin with higher efficiency than the literature known hepsin substrate RQLR↓VVGG. The introduction of d-amino acids on a selected peptide with the highest catalytic efficiency (k_cat/K_m) renders it resistant to cleavage by plasma or serum while maintaining their susceptibility to hepsin.

中文翻译：

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从计算机模拟到实验验证：为丝氨酸蛋白酶定制肽底物。

如今，用于将药物转运至肿瘤细胞的智能纳米载体在治疗癌症方面引起了极大的兴趣。使用酶刺激来裂解基于肽的药物纳米胶囊以选择性释放紧邻肿瘤细胞的纳米胶囊货物为癌症研究提供了新的可能性。在目前的工作中，我们展示了一种通过II型跨膜丝氨酸蛋白酶hepsin查找和优化可裂解底物序列的方法，该蛋白在前列腺癌中过度表达。针对肝素结合腔的计算机组合文库的设计和筛选，可以鉴定出具有高计算对接分数的一组有​​前途的底物。体外筛选验证了预测结果，并显示所有底物均被庚素裂解，其效率高于文献中已知的庚素底物RQLR↓VVGG。的简介所选肽上的d-氨基酸具有最高的催化效率（k _cat / K _m），使其对血浆或血清的裂解具有抵抗力，同时保持了对肝素的敏感性。