Which enzyme is involved in the disease Hyperphenylalaninemia, and what is its normal function?

A Phenylalanine hydroxylase, conversion of phenylalanine to tyrosine ✓
B Tyrosinase, conversion of tyrosine to melanin
C Tryptophan hydroxylase, conversion of tryptophan to serotonin
D Homogentisate oxidase, conversion of homogentisic acid to maleylacetoacetic acid

Explanation

Hyperphenylalaninemia is a genetic disorder caused by the deficiency of the enzyme phenylalanine hydroxylase, which is responsible for the conversion of phenylalanine to tyrosine.

Mnemonic

'Phe'nylalanine Hydroxylase = 'Phe' = Phenyl

Source

Guyton and Hall Textbook of Medical Physiology
Enzymes in Disease Biochemistry Amino Acid Metabolism Disorders Hard MEDICAL Confidence: high