<prompt> Enzyme deficient in alkaptonuria isHomogentisic acid oxidaseTyrosinase ITyrosinase IIAcid maltase  <response>: Ans. a Homogentisic acid oxidase. Ref. Harper, Biochemistry, 25th ed., 332Disorders of amino acid and urea cycle metabolismAmino acid metabolism NameEnzyme deficiencyMetabolism affected1AlbinismTyrosinaseTyrosine2AlkaptonuriaHomogentisate oxidasePhenylalanine, tyrosine3CystathioninuriaCystathionine lyaseCysteine, methionine, serine4HistidinemiaHistidine ammonia lyaseHistidine5HomocystinuriaCysthionine sythaseCysteine, methionine, serine6Maple syrup urine diseaseBranched-chain keto acid dehydrogenaseValine, isoleucine, leucine7PhenylketonuriaPKUPhenylanine hydroxylasePhenylalanine8TyrosinosisHydroxyphenylpyruvate hydroxylaseTyrosine transaminase Urea cycle1ArgininemiaArginase2ArgininosuccinaturiaArgininosuccinate lyase3CitrullinemiaArgininosuccinate synthetase4Hyperammonemia-IOrnithine transcarbamoylase5Hyperammonemia-llCarbamoyl-phosphate synthetase-l 