Tyrosinase activity in serum from patients with malignant melanoma
Agrup, P.; Carstam, R.; Wittbjer, A.; Rorsman, H.; Rosengren, E.
Acta Dermato-Venereologica 69(2): 120-124
1989
ISSN/ISBN: 0001-5555 PMID: 2564228 Document Number: 342825
A preparation procedure is presented for the determination of tyrosinase-catalysed stereo-specific dopa oxidase activity in serum. Purification is obtained by separation on a Phenyl-Sepharose hydrophobic interaction column, followed by Con-A-Sepharose chromatography. Five out of seven sera from patients with widespread melanoma metastases were found to contain detectable quantities of tyrosinase. There was no tyrosinase activity in seven sera from patients with other malignancies, nor in six other control sera from individuals without malignancies. One serum which showed high tyrosinase activity was processed as above and studied by SDS-PAGE. A dopa-reactive band with an apparent MW of 66 kD was present in the gel, i.e. at the same place as that of the soluble tyrosinase of cultured human malignant melanoma cells. The protein was found to have the same pI at isoelectric focusing, and eluted in the same way from the preparation columns, used, as did soluble tyrosinase.