3. Enzymes are classified by the reactions they catalyze 3.1 Trivial names are usually given to enzymes. 3.1.1 Many enzymes have been named by adding the suffix“-ase” to the name of their substrate or to a word or phrase describing their activity(type of reaction). 3.2 Enzymes are categorized into six major classes by international agreement 3.2.1 The six major classes include Oxidoreductases: catalyzing oxidation-reduction reactions Transferases: catalyzing the transfer of a molecular group from one molecule to another3. Enzymes are classified by the reactions they catalyze 3.1 Trivial names are usually given to enzymes. 3.1.1 Many enzymes have been named by adding the suffix “-ase” to the name of their substrate or to a word or phrase describing their activity (type of reaction). 3.2 Enzymes are categorized into six major classes by international agreement. 3.2.1 The six major classes include Oxidoreductases: catalyzing oxidation-reduction reactions. Transferases: catalyzing the transfer of a molecular group from one molecule to another