1. Molecular weight. Enzymes are substances of high molecular weight. 

2. Heat sensitivity. Enzymes are inactivated or destroyed by heat. Inactivation takes place even at very low temperatures. 

3. Catalytic properties. The enzymes speed up the reaction and the enzyme is unchanged after the reaction. Thus they act as catalyst. 

4. Turn over number. It is the number of substrate molecules which are acted upon by one molecule of enzymes just in one minute. Enzymes have high turn over number. 

5. Specificity of enzymes. Enzymes are highly specific in nature i.e. a particular enzyme can catalyse only a particular type of reaction.