Posted by jayaram in Catabolism of purines, nitrogen-containing heterocyclic compounds found in nucleic acids, leads to formation of uric acid, which is excreted in urine normally. Gout is an abnormality in which uric acid is produced in excess, leading to an increase of uric acid in blood and deposition of urate crystals in joints.
Clinical manifestations include inflammation, pain, swelling, and increased warmth of some joints, particularly the big toe. Uric acid is rather insoluble and some of the clinical symptoms of gout can be attributed to damage done by urate crystals. Crystals are phagocytes by cells in the joint and accumulate in digestive vacuoles that contain Lysosomal enzymes. Crystals cause physical damage to the vacuoles, releasing Lysosomal hydrolyases into the cytosol. Even though the pH optimum of Lysosomal enzymes is lower than the pH of the cytosol, they have some hydrolytic activity at the higher pH, which causes digestion of cellular components, release of substances from the cell, and cellular autolysis.