<unk>  (abbreviated as<unk>  or Y) or 4-hydroxyphenylalanine, is one of the 20 amino acids that are used by cells to synthesize proteins. This is a non-essential amino acid and it is found in large quantities in casein. In fact, the word<unk> " is from the Greek<unk> os, meaning cheese, as it was first discovered in 1846 by German chemist Justus von Liebig in the protein casein from cheese.
Tyrosine
Phenylalanine
Arginine
Asparagine
Citrulline
Sardine
Ethionine
Acetylleucine