IMMOBILIZATION OF ALKALINE-PHOSPHATASE BY SORPTION ON NA-SEPIOLITE

被引:27
作者
CARRASCO, MS
RAD, JC
GONZALEZCARCEDO, S
机构
关键词
ADSORPTION; ALKALINE PHOSPHATASE; CLAYS; ENZYME IMMOBILIZATION; ENZYME KINETICS; SOIL ENZYMES; SEPIOLITE;
D O I
10.1016/0960-8524(94)00115-H
中图分类号
S2 [农业工程];
学科分类号
0828 ;
摘要
Alkaline phosphatase from bovine intestinal mucous membrane was immobilized by sorption on Na-sepiolite in order to obtain an enzyme-clay complex for soil application. Optimum conditions for immobilization were: phosphate buffer 0.1 M at pH 7, 2 h of magnetic stirring at 4 degrees C, 0.25 mg ml(-1) for the concentration of enzyme and an enzyme/clay ratio of IO ml g(-1). The adsorption isotherm obeyed the Langmuir equation (r(2) 0.996 at P<0.001), reaching a maximum amount of enzyme retention. Apparent K-m values were 18.32 mM for the immobilized enzyme and 2.36 mM for the enzyme in aqueous solution; optimum pH (10.5) did not change as a consequence of immobilization; a first-order kinetic was obtained for incubation times of less than I h for both enzymes and the immobilized enzyme showed a lower incubation temperature optimum. The immobilized phosphatase showed less stability than the soluble enzyme in terms of storage at 30 degrees C, thermal stability and resistance to proteolytic attack.
引用
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页码:175 / 181
页数:7
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