| Modification Notes |
The biosynthesis of molybdenum cofactor is a highly conserved pathway that leads to the activation of molybdenum, a transitional element used as a metal hetero-atom in the active site of certain enzymes. MoCo Sulfurase (Molybdenum cofactor sulfurase), also known as HMCS and MOS, is a 888 amino acid enzyme that sulfurates molybdenum cofactor so that it can be utilized by xanthine dehydrogenase and aldehyde oxidase. Defects in the gene encoding MoCo Sulfurase is the cause of type II xanthinuria, a condition that is characterized by excretion of large amounts of xanthine in urine and the subsequent formation of xanthine stones. Due to the deficiencies of xanthine dehydrogenase and aldehyde oxidase, patients suffering from type II xanthinuria also cannot metabollize allopurinol into oxypurinol, leading to decreases in uric acid formation and purine synthesis. |