Studies on immobilization of urease and Co immobilization of cholesterol Esterase cholesterol oxidase and Peroxidase and their clinical Applications

Abstract

Activity and stability of immobilized urease on different matrices newline Nylon 6 6 beads sepharose gel silica gel and gelatin film coated on cellulose newlineacetate membrane have been investigated Different covalent coupling newlinemethods using ascorbic acid or glutaraldehyde for polyamine matrices and newlineperiodate for polyhydroxy matrix and tosyl chloride for silica gel were used newlineA relatively less expensive source of urease crude extract of jack bean meal newlinewas used Periodate oxidized sepharose CL 6B gel was able to retain 74 of newlinethe enzyme on immobilization while ascorbic acid coupling to gelatin film newlineretained 66 Immobilized urease on nylon 6 6 beads and gelatin film stored newlinein 50 mM phosphate buffer pH 8 at 4 C showed practically no leaching of newlinethe enzyme retaining the activity over a period of 30 days while urease newlinecoupled to sepharose and silica gel stored under the same conditions was newlinestable over a period of 10 days Immobilized urease retained activity over a newlinewide pH range and was more stable than the free enzyme at lower and higher newlinepH values Immobilized urease was also more stable than the free enzyme newlineover a wide temperature range Nylon 6 6 bead immobilized jack bean urease had a higher Km newline 0 62 mM than that of the soluble enzyme 0 55 mM Coefficients of newlinevariation within day and between successive days were 2 and 7 5 newlinerespectively A good correlation 0 99 was found between the blood urea newlineobtained by the present method and commercial available kit method newlineemploying free enzymes newline newline