3455
Unlike the majority of G protein - coupled receptors , the prostaglandin E ( 2 ) ( PGE ( 2 ) ) E - prostanoid 3 ( EP3 ) receptor binds agonist with high affinity that is insensitive to the presence of guanosine 5 [ prime ] - O - ( 3 - thio ) triphosphate ( GTP gamma S ) .
 Chemical: prostaglandin E ( 2 ); Chemical: PGE ( 2 ); Chemical: E - prostanoid; Chemical: guanosine 5 [ prime ] - O - ( 3 - thio ) triphosphate; Chemical: GTP gamma S
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: prostaglandin E ( 2 ); Chemical: PGE ( 2 ); Chemical: E - prostanoid; Chemical: guanosine 5 [ prime ] - O - ( 3 - thio ) triphosphate; Chemical: GTP gamma S