Harding-Passey mouse melanoma

The above results together with previous findings suggest that tryptophan could also be an alternative substrate for melanin synthesis. Chen and Chavin (60) used tryptophan as a substrate for goldfish tyrosinase while the incorporation of tryptophan in the melanin of Harding Passey mouse melanoma cells was reported by other authors (67). Tryptophan in a true melanin synthesizing system, i.e. in B16-F10 melanoma cells cultured in the presence of 2mM tryptophan, increased melanin formation on the second day (4J). 

Costa C, Allegri G, DeAntoni A (1975) Studies on Melanogenesis of Tryptophan in Harding-Passey Mouse Melanoma. Acta Vitaminol Enzymol 29 223... 

The oxidation of tyrosine to 3,4-dihydroxyphenylalanine (DOPA) is a well-established reaction that occurs enzymatically under the influence of tyrosinase. The presence of tyrosinase has been shown in mammalian tissues, a particularly good source being the Harding-Passey mouse melanoma. " Lemer et determined that the enzymatic activity for tyrosine and DOPA is associated with cytoplasmic particles and that the two activities are not separable. Preparations can be obtained which have a long induction period before the onset of the oxidation of tyrosine and... 

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