SOME PHYSICOCHEMICAL PROPERTIES OF CATHEPSIN H FROM HUMAN MENINGIOMA

Chornaya Valentina, Lyannaya Olga

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. V_max for cathepsin H from meningioma was found to be 3.5 times higher than that of normal brain tissue, whilst K_m 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 V_max value and lower molecular weight than the enzyme from normal human neocortex tissue, without alteration in its pH optimum and K_m value.