7979
Although cystine - knot peptides are available through chemical and recombinant synthetic routes , oxidative folding to afford the bioactive isomers still remains a crucial step .
 Chemical: cystine
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: cystine