4442
However , it remains unclear why the alpha sugar - binding site of EW29Ch binds to lactose much more strongly because the crystal structure of lactose - bound EW29Ch showed that the interaction between the alpha sugar - binding site and lactose was almost same as that between the gamma sugar - binding site and lactose .
 Chemical: sugar; Chemical: lactose; Chemical: sugar; Chemical: lactose; Chemical: sugar; Chemical: lactose
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
 Chemical: sugar; Chemical: lactose; Chemical: sugar; Chemical: lactose; Chemical: sugar; Chemical: lactose