Figure 3
Biosynthesis of urinary melanogens (14, 18). HA : homogentisic
acid; TH : tyrosine-3-hydroxylase (EC 1.14. 16.2); T: tyrosinase
(EC 1.14. 18. 1); A: adrenaline (epinephrine); EU: eumelanins;
FEO: pheomelanins; TRC: trichochromes; X: glucuronic or sulfuric
acid; DOPAC: dopac = 3,4-dihydroxyphenylacetic acid; HVA : homovanillic
acid; VLA : vanillactic acid; MOPA : "methoxydopa" (O-methyldopa,
3-methoxytyrosine, 3-methoxy-4-hydroxyphenylalanine); 5-S-CD:
5 -S-cysteinyldopa; 5H6M21C : 5-hydroxy-6-methoxy-2-indolylcarboxylic
acid; 6H5M21C: 6-hydroxy-5-methoxy-2-indolylcarboxylic acid; MM 2: probably dopa tetramer; PHPPA : p-hydroxyphenylpyruvic acid; DOPA : dopa = 3 ,4-dihydroxyphenylalanine; 5, 6DH21C: 5,6-dihydroxy-2-indolylcarboxylic acid; TPM: Thormählen positive melanogens (A, AX, B, C, D,
E). Small frame : dopaquinone; large frame : compounds
which were found in elevated amount in the urine of melanoma patients.
For further details see the text.
