Abstract
Abstract. Thymidine kinase (TK) was partially purified from adrenal tissues with adrenocortical hyperplasia, adenomatous hyperplasia, adenoma and carcinoma from patients with Cushing's syndrome and from normal adrenal glands. Adrenocortical carcinoma, adenoma, hyperplasia and nodule and hyperplastic portion of adenomatous hyperplasia contained higher concentration of TK than normal adrenal gland. By DEAE-cellulose column chromatography, adrenocortical carcinoma gave two peaks (Peak I and Peak II) of TK, while in other adrenal tissues the second peak (Peak II) was only slightly detected or hardly detected. TK in all these tissues was identical with respect to pH optimum, metal requirement and inhibition by dTTP. dCTP inhibited TK activities of normal adrenal gland and the hyperplastic portion of adenomatous hyperplasia by 55%, respectively, but hardly affected the activity of the nodule of adenomatous hyperplasia, adenoma, hyperplasia and carcinoma. TK from hyperplastic portion of adenomatous hyperplasia showed the intermediate heat stability between the heat-stable enzyme from normal adrenal gland and the heat-labile enzyme from adrenocortical carcinoma, adenoma, hyperplasia and the nodule of adenomatous hyperplasia. The apparent Km for thymidine from adenocortical carcinoma (Peak I and Peak II) was 5.0 and 11.1; adenoma, 4.8; hyperplasia, 5.5; adenomatous hyperplasia (nodule, 5.0 and hyperplastic portion, 19.8) and normal adrenal gland, 25.0 μm. These observations indicated that TK with different catalytic properties existed in various human adrenal tissues. They also demonstrated that TK isolated from the nodule of adrenocortical adenomatous hyperplasia had similar properties as adrenocortical adenoma, while TK from the hyperplastic portion had the intermediate catalytic properties between normal adrenal gland and adrenocortical hyperplasia.
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