enzyme classification

oxidoreductase

• catalyse oxidation-reduction reactions

• carbon inc in oxidation state

• nad is commonly involved

examples of oxidoreductases

• lactate dehydrogenase

• asocorbate oxidase

transferases

catalyse group transfer reaction

• via coenzyme or covalent intermediate

hydrolases

• catalyse hydrolysis reactions

• cleave a bond with addition of water to products

• eg proteases, lipases, esterases

most common class of enzyme

hydrolases

lyases

• catalyse lysis

• elimination reaction leaving a double bond

• no water added

synthases

• reverse of lyases

• create new bond using atp/free energy

• eg atp synthase

isomerases

• catalyse isomeric reactions

• molecular formula does not change

• eg racemases

isomerism

• transfer of groups within molecules to yield different structural or geometric isomers

ligases (synthetases)

• catalyse ligation of two substrates

• requires chemical energy eg atp hydrolysis

• example : dna ligase

smallest family of enzymes

ligases / synthetases