Which compound would be LEAST likely to appear in above-normal amounts in the urine of an infant with untreated phenylketonuria?

Question

Quizplus · Accepted Answer

Phenylketonuria (PKU) is an inherited disorder that causes the accumulation of phenylalanine in the blood due to the deficiency of phenylalanine hydroxylase enzyme. Because of this, phenylalanine is converted to various compounds such as phenylpyruvic acid, phenyllactic acid, phenylacetic acid, and others, which are excreted in the urine. The compound that would be least likely to appear in above-normal amounts in the urine of an infant with untreated PKU is tyrosine. This is because the conversion of phenylalanine to tyrosine requires the activity of phenylalanine hydroxylase, which is deficient in PKU patients. Therefore, tyrosine levels would be expected to be low in the urine of PKU patients.

Which Compound Would Be LEAST Likely to Appear in Above-Normal