The Enzyme Commission number consists of the letters "EC" followed by four numbers separated by a special character, where those numbers represent a progressively finer classification of the enzyme, like the EC 3 where the enzymes are hydrolases, and EC 3.4 are hydrolases that act on peptide bonds.
Every enzyme code consists of the letters "EC" followed by four numbers separated by periods. Those numbers represent a progressively finer classification of the enzyme. EC 3 enzymes are hydrolases (enzymes that use water to break up some other molecule) EC 3.4 are hydrolases that act on peptide bonds The Enzyme Commission number (EC number) is a numerical classification scheme for enzymes, based on the chemical reactions they catalyze. 
