| Hormones | Enzymes |
| 1. Hormones may be amino acid derivatives, peptides, proteins or steroids in nature. | 1. All enzymes are complex proteins. |
| 2. They have low molecular weight and often readily diffuse through cell membranes. | 2. They have very high molecular weight and are not diffusible. |
| 3. They are secreted by cells at one site and pass via blood to another site to act. | 3. They are secreted by cells and may act in the cells themselves or pass via ducts to act in some cavity in the body. |
| 4. They are used up in their regulatory action. | 4. They remain unaffected in the reaction they catalyze. |
| 5. They may act slowly or quickly. | 5. They act quickly. |
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RNA |
DNA |
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1. RNA is genetic material only in some viruses.
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1. It is genetic material of all organisms having cellular structure. 2. It has deoxyribose sugar in it. |
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Inorganic catalysts |
Enzymes |
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1. These are simple mineral ions or small molecules. 2. These can catalyse diverse reaction. 3. They are not regulated by any regulator molecules. 4. They are less sensitive to temperature and pH. 5. They have low molecular weight. |
1. These are proteins with complex three dimensional structures. 2. They catalyse only specific reactions of a single or only a few substrates. 3. They can be regulated by specific molecules which can change conformation and hence activity. 4. They are more sensitive to change in temperature and pH. 5. They have high molecular weight. |
i. stabilizing the transition state (substrate+enzyme complex) of a reaction.
ii. providing an alternative reaction pathway for a biological reaction.
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.
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