8310
A consequence of the ' target - first , pharmacology - second ' strategy is that many predicted drug targets are non - enzymes , such as scaffolding , regulatory or structural proteins , and their activities are often dependent on protein - protein interactions ( PPIs ) .
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Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
 None