3.1.2. Enzyme Classification
There are approximately 3000 known enzymes. These enzymes are classified into six categories based on the type of reaction they catalyze.
1. Oxidoreductase: Oxidizes or reduces by transfer of hydrogen
2. Transferase: Transfers C-, N-, P-, or S-containing functional groups such as aldehydes and ketones, glycosils, acyls, phosphates, and sulfur containing groups.
3. Hydrolase: Hydrolyzes esters, anhydrides, peptide bonds, other C-N bonds, glycosides.
4. Lyase: Adds to double bonds:
> C = C <
> C = O
> C = N
5. Isomerase: Isomerizes optical isomers
6. Ligase: Splits C-C, C-O, C-N, C-S and C-halogen bonds without hydrolysis or oxidation, mostly with ATP.