15058
In a previous study , a disulfide constrained cyclic peptide cyclo S ( 1 ) , S ( 9 ) Cys - Glu - Thr - Gly - Ala - Lys - Pro - His - Cys ( S ( 1 ) , S ( 9 ) - cyclo - CETGAKPHC ) was isolated from a phage displayed cyclic peptide library using an affinity selection method against HBV surface antigen ( HBsAg ) .
 Chemical: disulfide; Chemical: cyclo S ( 1 ) , S ( 9 ) Cys - Glu - Thr - Gly - Ala - Lys - Pro - His - Cys
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: disulfide; Chemical: cyclo S ( 1 ) , S ( 9 ) Cys - Glu - Thr - Gly - Ala - Lys - Pro - His - Cys