One of 22 amino acids use by human cells to synthesize proteins, this non-essential amino acid has its own polar side groups and derives its name from the Greek word tyros, which means cheese. Discovered by Justus von Liebig, a German chemist, in 1846, tyrosine is primarily found in the protein casein which is the protein present in most cheeses. Recommended daily intake for this amino acid is 25 mg per kilogram of body weight, or roughly 11 mg per pound. Tyrosine can also be synthesized in the human body from phenylalanine, and is found in high protein foods like turkey, fish, chicken, milk, cottage cheese, peanuts, yogurt, almonds, pumpkin seeds, soy products, sesame seeds, avocados, lima beans, and bananas. To gauge how much tyrosine one consumes, a typical egg white has 250 mg per egg, and lean beef/lamb/pork/chicken/salmon/turkey contains roughly 1000 mg per 3 ounce portion.