17730
The S . aureus NAL which contains no natural cysteine residues was subjected to site - directed mutagenesis to introduce a cysteine in place of Lys165 in the enzyme active site .
 Chemical: cysteine; Chemical: cysteine; Chemical: Lys165
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: cysteine, cysteine, Lys165 
Answer:
 Chemical: cysteine; Chemical: cysteine; Chemical: Lys165