L-Tyrosine is a proteinogenic polar amino acid, deemed not essential because it can be synthesized by the human body. As a member of the amino acid group that is being used by cells to build proteins, this building block derived its name from the Greek word tyros, which means cheese, because it was discovered in the cheese protein casein. L-Tyrosine can be synthesized from phenylalanine and can be found in foods high on protein, like soy products, poultry, cheese, bananas, dairy products and several seeds, including the sesame seeds. The unique phenol functionality and the occurrence in proteins that belong to the signal transduction process, make this amino acid different. Tyrosine can be converted by tyrosine hydroxylase enzyme into levodopa, a psychoactive drug that is used, among other uses, for clinical treatment of Parkinson’s disease. It is also involved in the synthesis of dopamine, norepinephrine and epinephrine.