PDF(Pubmed)
Abstract：
Neutrophil elastase (HNE), like other members of the so-called GASPIDs (Granule-Associated Serine Peptidases of Immune Defense), is activated during protein biosynthesis in myeloid precursors and stored enzymatically active in cytoplasmic granules of resting neutrophils until secreted at sites of host defense and inflammation. Inhibitors thus could bind to the fully formed active site of the protease intracellularly in immature progenitors, in circulating neutrophils, or to HNE secreted into the extracellular space. Here, we have compared the ability of a panel of diverse inhibitors to inhibit HNE in the U937 progenitor cell line, in human blood-derived neutrophils, and in solution. Most synthetic inhibitors and, surprisingly, even a small naturally occurring proteinaceous inhibitor inhibit HNE intracellularly, but the extent and dynamics differ markedly from classical enzyme kinetics describing extracellular inhibition. Intracellular inhibition of HNE potentially affects neutrophil functions and has side effects, but it avoids competition of inhibitors with extracellular substrates that limit its efficacy. As both intra- and extracellular inhibition have advantages and disadvantages, the quantification of intracellular inhibition, in addition to classical enzyme kinetics, will aid the design of novel, clinically applicable HNE inhibitors with targeted sites of action.
摘要：
中性粒细胞弹性蛋白酶(HNE),像所谓的GASPID（免疫防御颗粒相关丝氨酸肽酶）的其他成员一样，在骨髓前体的蛋白质生物合成过程中被激活，并在静息中性粒细胞的细胞质颗粒中具有酶活性，直到在宿主防御和炎症部位分泌。因此，抑制剂可以在未成熟祖细胞的细胞内与蛋白酶的完全形成的活性位点结合，在循环中性粒细胞中，或HNE分泌到细胞外空间。这里,我们已经比较了一组不同的抑制剂在U937祖细胞系中抑制HNE的能力，在人类血液来源的嗜中性粒细胞中，和解决方案。大多数合成抑制剂，令人惊讶的是,即使是一个小的天然存在的蛋白质抑制剂抑制HNE细胞内，但是程度和动力学与描述细胞外抑制的经典酶动力学明显不同。HNE的细胞内抑制可能影响中性粒细胞功能并具有副作用，但它避免了抑制剂与限制其功效的细胞外底物的竞争。由于细胞内和细胞外抑制都有优点和缺点，细胞内抑制的定量，除了经典的酶动力学，将有助于小说的设计，具有靶向作用位点的临床适用的HNE抑制剂。
