2334
The first TFT alpha - bungarotoxin was isolated almost half a century ago and so far it remains a valuable tool in the study of nicotinic acetylcholine receptors .
 Chemical: acetylcholine
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
 Entities: acetylcholine 
Answer:
 Chemical: acetylcholine