In Phenylketonuria (PKU), an Enzyme That Converts One Amino Acid

Multiple Choice

In phenylketonuria (PKU) , an enzyme that converts one amino acid into another does not work properly. Which of the following is the most likely cause of this genetic condition?

A) an error in the transcription of the gene for the enzyme
B) a mutation in the DNA sequence that codes for the enzyme
C) an excess of the amino acids necessary to produce the enzyme
D) a structural variation in the amino acid modified by the enzyme