Lyases

Carbon bonds can be cleaved in oxidation and hydrolysis reactions. They can also be cleaved when two substrates form one product or when one substrate forms two products. When the CO₂  or H₂O is released a double bond will form. Lyases are the enzymes which catalyse these reactions.

An example which illistrates this is the conversion of fructose 1,6-bisphosphate (6 carbon compound) into dihydroxyacetone phosphate and glyceraldehyde 3-phosphate (both 3 carbon compounds).