Table 1. Enzymatic activity of Dct and tyrosinase, content of melanin and thiol in non-agouti black versus Dct-mutant melanocytes in culture.

	Melanin content*				Enzymatic activity‡			Thiol content§
Phenotype	PTCA-eumelanin	4-AHP-pheomelanin	Total melanin†	PTCA/total melanin†	Dct	Tyrosinase	Melanin formation	Cysteine	Glutathione
Non-agouti black	1280±16	26±0.5	599	2.14	23.58±0.82	26.20±8.55	53.30±3.29	0.27	2.78
Slaty	53±3	130±10	81	0.66	8.36±0.16	25.81±1.42	61.46±4.77	0.27	3.07
Slaty light	302±39	662±21	198	1.53	0.88±0.02	23.45±3.66	60.56±2.77	0.60	0.29

* Expressed in ng/10⁶ cells.

† Expressed in terms of A₅₀₀×1000/10⁶ cells.

‡ Expressed in terms of pmol·(μg of protein)⁻¹·h⁻¹.

§ Expressed in terms of nmol/10⁶ cells.