Is it "I could care less" or "I couldn't care less"?
amino acid, 1857, coined 1846 by German chemist Baron von Justus Liebig (1802-1873), who had first obtained it a year before, from Greek tyros "cheese" + chemical suffix -ine (2). So called because it was easily obtained from old cheese.
tyrosine ty·ro·sine (tī'rə-sēn')
A white crystalline amino acid that is derived from the hydrolysis of proteins such as casein and is a precursor of epinephrine, thyroxine, and melanin.
A nonessential amino acid. Chemical formula: C9H11NO3. See more at amino acid.