Comparative study of the amino acid composition of some tumor and normal melanosomes

The amino acid composition of melanosomes from human and Harding-Passey mouse melanomas and from pigmented tissues of cattle eyes isolated according to BOLT was studied. The 18 current amino acids and moreover dopa were found in all the hydrolysates studied. By means of apolar/polar amino acid ratio suggested by HATCH the possible properties of melanosomal protein(s) were infered. The higher level of cysteine and lysine in mouse melanosomes as compared with tyrosinase supports the theory of special matrix protein in melanosomes. Lysine seems to have a role in regulation of the quantity of synthesized melanin.