SOME PHYSICOCHEMICAL PROPERTIES OF CATHEPSIN H FROM HUMAN MENINGIOMA
Aim: To compare some physicochemical properties of cathepsin H from human brain tumors and normal brain tissues. Methods: The enzyme was isolated from normal human brain tissue and fibrous meningioma and purified by methods of homogenization, saturation by (NH4)2SO4 (30–80% saturation), followed by Concanavalin A and Azocazein-Sepharose chromatographies and gel filtration on Sephadex G-100 (75). Results: Cathepsin H was purified by 1795-fold from normal human brain tissue and by 2457-fold — from meningioma tissue. Vmax for cathepsin H from meningioma was found to be 3.5 times higher than that of normal brain tissue, whilst Km of the enzyme from tumor tissue is 1.3 times lower than that from normal human brain. The molecular weights of cathepsin H from normal human brain tissue and meningioma were 28 kDa and 25 kDa respectively. Conclusion: Cathepsin H isolated from human fibrous meningioma with microconcentric structures possesses higher activity levels and Vmax value and lower molecular weight than the enzyme from normal human neocortex tissue, without alteration in its pH optimum and Km value.
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