A patient complains of knee pain Routine investigations are unremarkable and still the patient is unsatisfied Urine turns black on standing what is the enzyme involved: (A) Homogentisate Oxidase, (B) Xanthine oxidase, (C) Phenylalanine hydroxylase, (D) Dihydroorlate Dehydrogenase
Answer is A. REF : LIPPINCOTT 6TH ED