Enzyme Reaction Mechanisms Class Notes

Each enzyme has a specific three dimensional shape which includes an area where the biochemical transformation takes place, called the active site. The active site contains a specialized amino acid sequence that facilitates the conversion of substrate(s) to product(s) . Within the active site are two sub-sites, the binding site and the catalytic site (they may be the same or there is a lot of overlap). The binding site contains residues which cause the substrate to bind to the enzyme by ionic, H-bonding or electrostatic forces. If a molecule binds to the active site and binds to the enzyme, it is said to have affinity for the active site.The catalytic site usually contains amino acid residues which carry out the actual transformation. The afore mentioned 6 enzyme classes need to be named in order, they have to named in the sequence – oxidoreductases, transferases, hydrolases, lyases, isomerases, and ligases. The difference between hydrolases and lyases is that hydrolases uses water to breakdown molecules whereas lyases don’t. Ligases are also called synthetases. The order of the classification in the picture above is wrong, use it for examples and explanation