Master Enzyme Types with Picmonic for Medicine

There are six fundamental types of enzymes. Lyases catalyze bond cleavage (typically C-C, C-N, or C-O) through elimination, which leaves double bonds or rings. Hydrolases also catalyze bond cleavage, but do so through the addition of water across the bond (one side gets an OH while the other side gets an H). Transferases catalyze the transfer of a group (i.e. methyl) from one compound to another. Isomerases catalyze structural or geometric changes within a molecule, in essence reordering the molecule. Oxidoreductases catalyze oxidation and reduction reactions in molecules. Finally, ligases catalyze the joining of two molecules, typically coupled with the hydrolysis of a phosphate bond from ATP. Almost all enzymes can be classified into these six categories, which are based on the types of reactions they catalyze. Kinases are a notable exception, which catalyze the phosphoryl transfer reaction from a phosphate donor to a receiving molecule.