In Alkaptonuria deficiency is:

Alkptonuria: Defect in catabolism of Tyrosine and Phenylalanine. Enzyme deficient is Homogentisate Dioxygenase (new name) or Homogentisate oxidase (old name) Note: If both names are given mark Homogentisate Dioxygenase. Urine turns black on exposure to air due to oxidation of homogentisic acid. Homogentisic acid is an intermediate in the catabolism of Tyrosine. Dark staining of diapers Deposition of black pigments (polymerization of homogentisic acid occurring in body over years) in joints, cailage and collagenous tissue, known as ochronosis. Option 1- Phosphofructo kinase RLE enzyme of glycolysis. Option 2 HMG CoA reductase - RLE enzyme of cholesterol synthesis Option 4 Xanthine oxidase -Rate limiting enzyme of purine catabolism