Departamento de Bioquímica, Universidade Federal de São Paulo-Escola Paulista de Medicina, Rua Três de Maio, 100 Vila Clementino, 04044-020 São Paulo, SP, Brazil.
Int J Biol Macromol. 2010 Nov 1;47(4):551-7. doi: 10.1016/j.ijbiomac.2010.07.011. Epub 2010 Aug 6.
rBbKI and rBbCI, plant recombinant inhibitors from Bauhinia bauhinioides, and BpuTI from Bauhinia purpurea seeds distinctly and specifically block proteolytic enzymes. The secondary structures of those inhibitors were compared and their interactions with phospholipid vesicles were evaluated by the release of calcein and by intrinsic fluorescence of tryptophan residues. The results show that rBbKI, rBbCI and BpuTI are able to interact with phospholipd vesicles and induce membrane permeabilization in a concentration- and pH-dependent manner. The leakage was rapid and extensive at pH 4.5, but at physiological pH, no calcein release was observed. These results may suggest that upon inflammation or microorganism invasion accompanied by lowering of pH, appropriate conditions may occur for the inhibitors to interact with cell membrane and act on specific proteolytic enzyme.
rBbKI 和 rBbCI 是来自羊蹄甲属植物的植物重组抑制剂，BpuTI 则来自于羊蹄甲属植物的种子，它们能够特异性地阻断蛋白水解酶。本文比较了这些抑制剂的二级结构，并通过钙黄绿素的释放和色氨酸残基的固有荧光评估了它们与磷脂囊泡的相互作用。结果表明，rBbKI、rBbCI 和 BpuTI 能够与磷脂囊泡相互作用，并在浓度和 pH 值依赖性的方式下诱导膜通透性。在 pH 值为 4.5 时，泄漏迅速且广泛，但在生理 pH 值下，没有观察到钙黄绿素释放。这些结果可能表明，在炎症或微生物入侵伴随 pH 值降低的情况下，可能会出现适当的条件，使抑制剂与细胞膜相互作用并作用于特定的蛋白水解酶。
