The body normally makes tyrosine from the essential amino acid:

Question

Quizplus · Accepted Answer

Tyrosine is made from the essential amino acid phenylalanine through a process called hydroxylation, which requires the presence of an enzyme called phenylalanine hydroxylase. In individuals with a deficiency in this enzyme, phenylalanine cannot be converted to tyrosine, leading to a condition known as phenylketonuria (PKU). Therefore, the correct choice is A, phenylalanine.

The Body Normally Makes Tyrosine from the Essential Amino Acid