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Tyrosine utilization by pigmented hamster melanoma cells cultured in vitro
Author(s) -
Ulrich Kay,
Tritsch George L.,
Moore George E.
Publication year - 1968
Publication title -
international journal of cancer
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.475
H-Index - 234
eISSN - 1097-0215
pISSN - 0020-7136
DOI - 10.1002/ijc.2910030405
Subject(s) - tyrosine , melanin , hamster , in vitro , cell culture , biology , tissue culture , biosynthesis , melanoma , cell , biochemistry , microbiology and biotechnology , cancer research , enzyme , genetics
A pigmented hamster melanoma cell line MM No. 2 (RPMI No. 3460), cultured in vitro for more than two years, showed a very high utilization of tyrosine in the culture medium as compared to a non‐pigmented hamster melanoma cell line 3AA (RPMI No. 1856). The MM No. 2 cells used from 2.4 to 8.3 × 10 −9 μmoles/cell/hr, and the 3AA cells used from 0.1 to 2.9 × 10 −9 μmoles/cell/hr of tyrosine. Phenylalanine was not converted to tyrosine in any appreciable amounts at any levels of tyrosine in the medium. Increasing amounts of melanin were synthesized by the MM No. 2 cells cultured at increasing levels of tyrosine. The biosynthesis of melanin was maximal at a concentration of 0.60 mM of tyrosine in the medium and did not increase further if the tyrosine content was increased beyond this value. A higher tyrosine concentration than commonly employed in culture media thus seems necessary to secure a maximal melanin biosynthesis in a culture of cells capable of melanin formation. Melanin biosynthesis first began after 3 to 6 days of culture, probably coinciding with the cessation of cell multiplication in the cultures, supporting the concept that cell multiplication and differentiated function are antagonistic processes.