This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Proteins and Amino Acids, Subject name: Biochemistry
[{'content': 'Which enzyme defect causes phenylketonuria? \nSelect and explain. \nA. Phenylalanine oxidase, B. Phenylalanine hydroxylase, C. Tyrosinase, D. Tyrosine transaminase', 'role': 'user'}, {'content': "Answer: B \nExplanation: Ans. is 'b' i.e., Phenylalanine hydroxylaseMetabolic diseaseEnzyme deficientMaple syrup urine diseaseBranched chain ketoacid dehydrogenaseMethyl-melonic aciduriaMethyl-malonyl CoA mutase (isomerase)Sweaty feet odor in bodyIsovaleryl-CoA dehydrogenaseTyrosinemia I (Tyrosinosis)Fumarylacetoacetate hydroxylaseTyrosinemia IITyrosine transaminase (Tyrosine aminotransferase)Neonatal tyrosinemiaHydroxyphenyl pyruvate hydroxylaseAlbinismTyrosinaseAlkaptonuriaHomogentisate oxidasePhenylketonuriaPhenylalanine hydroxylaseOrotic aciduriaOMP decarboxylaseHomocystinuriaCystathionine synthataseLesh-Nyhan syndromeComplete deficiency of enzyme HGPRTCystinosisCystine reductase", 'role': 'assistant'}]