the poorly hydrolysable gtp analogues guanosine 5'-0- ( 3-thiotriphosphate ) ( gtpgammas ) , guanylyl imidodiphosphate ( gpp [ nh ] p ) and guanylyl ( beta , gamma methylene ) diphosphonate ( gpp [ ch ( 2 ) ] p ) produced large increases in the frequency of ; discrete events ' that were recorded from photoreceptors in darkness .
C0018353
gtp
C0018366
gpp [ nh ] p