The combination of modified antioxidant enzymes for anti-thrombotic protection of the vascular wall: the significance of covalent connection of superoxide dismutase and catalase activities

Abstract

Vascular wall protection can be achieved by preventive attachment to the vascular wall of antioxidants and elimination/neutralization of toxic products after their disproportioning. For this purpose we have prepared covalent conjugates between the vascular wall glycosaminglycan chondroitin sulfate (CHS) and the antioxidant enzymes superoxide dismutase (SOD) and catalase (CAT). The following conjugates were obtained: SOD-CHS, CAT-CHS and SOD-CHS-CAT. Their anti-thrombotic activity was compared in a rat model of arterial thrombosis by measuring the time of occlusion emergence and thrombus mass. It is noteworthy that the effectiveness of single bolus injections of SOD-CHS/CAT-CHS mixture was much lower than that of the bienzymic SOD-CHS-CAT conjugate. The conjugate SOD-CHS-CAT proved to be anti-thrombotically effective in doses two orders of magnitude lower than the native biocatalysts and an order of magnitude lower than SOD-CHS and CAT-CHS derivatives. For effective anti-thrombotic protection in oxidative conditions it is important to maintain the stable connection of SOD and CAT activity on the vascular wall and the large size of these conjugates. Covalent conjugate SOD-CHS-CAT is the best prospect for pharmaceutical development.

Enzymatic Antioxidants: Next Phase of Pharmacological Effort to Fight Oxidative Stress?

“…The simultaneous action of SOD and CAT in area of lesion development was required to demonstrate the reliable effect of treatment. It became possible due to the obtaining the bienzyme conjugate, where SOD-1 was covalently bounded through glycosaminoglycan of the vascular wall, chondroitin sulphate (CHS), with CAT (the received adduct SOD-CHS-CAT) [41]. Such conjugation contributed to likening of SOD-1 to SOD-3 (really, EC-SOD is a glycoprotein [29][30][31]), and rendered to the received derivative biochemically coupled SOD-and CAT-activity (when the product of SOD reaction, hydrogen peroxide, is the substrate for the following CAT transformation in water and molecular oxygen being safe in such conditions; chemical reactions are given below).…”

Experimental Antioxidant Biotherapy for Protection of the Vascular Wall by Modified Forms of Superoxide Dismutase and Catalase

“…This is probably due to different vascular surface distribution of the derivatives. This phenomenon is partially controlled by using the SOD-CHS-CAT bienzyme conjugate [91]. The effective dose of the bienzyme conjugate, i.e.…”

Biopharmacology of Enzyme Conjugates: Vasoprotective Activity of Supramolecular Superoxide Dismutase-Chondroitin Sulfate-Catalase Derivative

“…4) and also to its unique supramolecular structure, mediated by CHS (curves 1 and 3 in Fig. 4) [11, 17]. Indeed, β-galactosidase (similar in molecular size to SOD-CHS-CAT) used in the same experimental scheme in equimolecular protein concentrations did not inhibit the ADP-induced platelet aggregation.…”

“…At a concentration of 500 U/ml, the SOD-CHS-CAT conjugate lowered the amplitude response to H 2 O 2 more effectively than CAT. The protective effect expressed by SOD-CHS-CAT may be connected to its affinity to the vascular wall (due to the conjugation of SOD with CAT via glycosaminoglycan of endothelial glycocalyx [11, 17]) and/or to the presence of SOD and endogenous NO in the model system. In the system described above, it is difficult to estimate the sorption of enzyme derivates because of the flow of vascular reactions not only from within outwards, but also from without inwards (i.e.…”