ISOLATION, PURIFICATION, AND COMPARATIVE CHARACTERISTICS OF ADENOSINE-DEAMINASE FROM 5 BOVINE BRAIN-TISSUE FRACTIONS

Adenosine deaminase was isolated and purified from five brain tissue f ractions: white and gray matters of the large hemispheres, cerebellum, medulla oblongata, and pituitary anterior lobe. The pH optimum, K-m, molecular weight, yield, and specific activities were determined for e ach of the enzyme preparations. Differences in the enzyme from the var ious brain tissues were observed by gel filtration and electrophoresis . Bivalent copper ions (Cu2+) were shown to irreversibly inhibit the a ctivity of the enzyme. Studies on the effect of sulfhydryl reagents su ggest that sulfhydryl groups are not essential for the catalytic activ ity of adenosine deaminase.