a white, crystalline nonessential amino acid, CHOHCHCH(NH)COOH, formed by the decomposition of proteins, as in the putrefaction of cheese
See tyrosine in American Heritage Dictionary 4
(tīˈrə-sēnˌ)
noun
A white crystalline amino acid, C9H11NO3, that is obtained from the hydrolysis of proteins such as casein and is a precursor of epinephrine, thyroxine, and melanin.