TYROSINASE ACTIVITY IN THE SERUM OF PATIENTS WITH MALIGNANT-MELANOMA

We have recently described a new method for measurement of tyrosinase activity in small amounts of human serum (100 mu l), where the purific ation of tyrosinase is obtained by adsorption of the enzyme to concana valin A sepharose, The method, which measures stereospecific dopa oxid ation, was used in the winter of 1992-93 for the measurement of activi ty in serum obtained from 30 healthy subjects and from 10 patients wit h melanoma metastases. The serum tyrosinase values in the 30 subjects ranged from 0.1 to 1.0 nkatal/l, and the mean value and standard devia tion was 0.4 +/- 0.2 nkatal/l. In the 10 patients with melanoma, the t yrosinase serum values ranged from 1.1 to 10.6 nkatal/l, and the mean value was 3.1 nkatal/l.