Phenylketonuria (PKU) is caused due to a deficiency of which enzyme?
Phenylalanine hydroxylase
Tyrosine hydroxylase
Aspartate transaminase
Alanine transaminase
Phenylketonuria (PKU) is a genetic disorder caused due to the deficiency of the enzyme phenylalanine hydroxylase (PAH). This enzyme is responsible for converting the amino acid phenylalanine into tyrosine in the liver. In individuals with PKU, the deficiency of PAH leads to the accumulation of phenylalanine and its toxic by-products in the body, which can cause severe neurological problems if left untreated. Hence option A is correct.
Option(B) Tyrosine hydroxylase is not the correct answer as this enzyme is responsible for converting tyrosine into L-DOPA, a precursor of the neurotransmitter dopamine, and is not related to the metabolism of phenylalanine. Hence option B is incorrect.
Option(C) Aspartate transaminase and Alanine transaminase are enzymes involved in amino acid metabolism, but they are not related to the metabolism of phenylalanine. Hence option C is incorrect.
Option(D) Aspartate transaminase and Alanine transaminase are enzymes involved in amino acid metabolism, but they are not related to the metabolism of phenylalanine.Hence option D is also incorrect.