19378
Having identified and improved the hinge - binding " warhead " at one end of their lead molecule , they proceeded to use structure - based design tools to guide modification of the other end to enhance selectivity over a closely related isoform of the kinase .
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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