Purines come with the foods you eat that come to a larger or lesser degree from the nucleus of what were living cells. The body metabolites these and converts them into uric acid. The uric acid is...
This will only occur if the alpha carbon to the carbonyl group can be protonated. The keto form of acetone (for example), would be a -CH2COCH3. The alpha carbon has lost a hydrogen and is negatively...