Sorbi D, Fadly M, Hicks R, Alexander S, Arbeit L
Department of Medicine, SUNY at Stony Brook.
Kidney Int. 1993 Dec;44(6):1266-72. doi: 10.1038/ki.1993.378.
Gelatinases are metalloproteinases in the kidney which can cleave type IV collagen as well as gelatin. We partially purified the 72 kDa and 92 kDa gelatinases. The gelatinolytic activity was measured by zymography and a quantitative biotin-avidin assay. By zymography, captopril in concentrations of 20 mM and 40 mM added to the incubation buffer reduced the gelatinolytic activity in a dose-dependent manner. The addition of zinc in a concentration of 50 to 100 microM reversed most of the inhibitory effect of captopril. By the biotin-avidin assay, captopril in a concentration of 30 to 50 nM reduced half of either the 72 kDa or 92 kDa gelatinolytic activity. Zinc in a concentration of 50 microM completely reversed the inhibitory effect of 1 microM captopril on both gelatinases. Lisinopril, a non-sulfhydryl ACE inhibitor, similarly inhibited the gelatinases, but a 100-fold higher concentration of the drug was needed. These findings suggest that captopril reversibly inhibits the 72 kDa and 92 kDa metalloproteinases by interacting with the zinc ion at their active sites. This inhibitory effect is observed with captopril levels comparable to the concentrations needed to inhibit the angiotensin converting enzyme in vivo and may at least partially explain some of the renoprotective effects seen with this drug.
明胶酶是肾脏中的金属蛋白酶，能够切割IV型胶原以及明胶。我们对72 kDa和92 kDa的明胶酶进行了部分纯化。通过酶谱法和定量生物素-抗生物素蛋白测定法测量明胶酶活性。通过酶谱法，向孵育缓冲液中添加浓度为20 mM和40 mM的卡托普利，明胶酶活性呈剂量依赖性降低。添加浓度为50至100 microM的锌可逆转卡托普利的大部分抑制作用。通过生物素-抗生物素蛋白测定法，浓度为30至50 nM的卡托普利可使72 kDa或92 kDa明胶酶活性降低一半。浓度为50 microM的锌可完全逆转1 microM卡托普利对两种明胶酶的抑制作用。赖诺普利，一种非巯基血管紧张素转换酶抑制剂，同样抑制明胶酶，但需要100倍更高浓度的药物。这些发现表明，卡托普利通过与72 kDa和92 kDa金属蛋白酶活性位点的锌离子相互作用，可逆地抑制这些酶。在体内，卡托普利抑制这些酶的浓度与抑制血管紧张素转换酶所需的浓度相当，这种抑制作用可能至少部分解释了该药物的一些肾脏保护作用。
