Centro de Malária e Doenças Tropicais, Instituto de Higiene e Medicina Tropical, Lisboa, Portugal.
Acta Trop. 2012 Jan;121(1):1-5. doi: 10.1016/j.actatropica.2011.09.008. Epub 2011 Oct 1.
BbiCPL1 was the first papain-like cysteine protease from a piroplasm to be identified with proteolytic activity. Here we report the improved production of the active recombinant enzyme, and the biochemical characterization of this potential drug target. BbiCPL1 showed characteristic properties of its class, including hydrolysis of papain-family peptide substrates, an acidic pH optimum, requirement of a reducing environment for maximum activity, and inhibition by standard cysteine protease inhibitors such as E-64, leupeptin, ALLN and cystatin. The optimum pH for the protease activity against peptide substrates was 5.5, but enzymatic activity was observed between pH 4.0 and pH 9.0. At slightly basic pH 7.5, BbiCPL1 maintained 83% of maximum activity, suggesting a role in cytosol environment.
BbiCPL1 是首个被鉴定具有蛋白水解活性的梨形虫木瓜样半胱氨酸蛋白酶。本文报道了活性重组酶的改良生产，并对这一潜在药物靶点进行了生化特征分析。BbiCPL1 表现出该酶类的典型特性，包括对木瓜蛋白酶家族肽底物的水解、酸性 pH 最佳值、还原环境下最大活性的需求以及受标准半胱氨酸蛋白酶抑制剂（如 E-64、亮抑酶肽、ALLN 和半胱抑素）抑制。该蛋白酶对肽底物的最适 pH 为 5.5，但在 pH4.0 到 pH9.0 之间可观察到酶活性。在略碱性 pH7.5 时，BbiCPL1 保持最大活性的 83%，表明其在细胞质环境中有作用。
