Steps in the correlation of structure with biological action

The concept of receptors . The receptor as an enzyme or other protein. 23 

The receptor as a nucleic acid, or as a coenzyme or other small molecule. Other aspects of receptors. 31 

How a small change in a molecule can lead to large changes in biological properties. 39 Correlations today. 49 

Steps in the correlation of structure with biological action 

Fundamental to any study of correlations, between structure and biological activity, is knowledge that the messengers and coenzymes of each organism depend strongly on small details of their chemical structure without which their characteristic biological effect is lost. If these details are varied, even slightly. 

Before plunging into these details, it will help to stand back a little and take a broader view of how the ideas of structure-activity relationships arose. 

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