Asked in UHS MDCAT 2009 2009Moderate

In phenylketonuria, phenylalanine is not degraded because of defective enzyme:

Correct answer: A. Phenylalanine hydroxylase

  • A. Phenylalanine hydroxylase
  • B. Phenylalanine oxidase
  • C. Phenylalanine phosphate
  • D. None of these

Explanation

Explanation:Phenylalanine hydroxylase is an enzyme that converts the amino acid phenylalanine to tyrosine. In PKU, genetic mutations result in a deficiency or absence of functional phenylalanine hydroxylase, leading to the buildup of phenylalanine and its by products in the blood and tissues.Phenylalanine oxidase is not a human enzyme and is not involved in the normal metabolism of Phenylalanine.Phenylalanine phosphate is not an enzyme but a metabolic intermediate of phenylalanine that is not directly involved in the pathogenesis of PKU.

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