18736
Several crystal structures of GH20 beta - N - acetylhexosaminidases , which release monosaccharide GlcNAc from its substrate , have been determined , but to date , a structure of lacto - N - biosidase is unknown .
 Chemical: N; Chemical: monosaccharide; Chemical: GlcNAc; Chemical: N
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: N; Chemical: monosaccharide; Chemical: GlcNAc; Chemical: N