four acyclic guanosine analogs , the ( r ) and ( s ) enantiomers of 9- ( 3,4-dihydroxybutyl ) guanine , 9- ( 4-hydroxybutyl ) guanine , and acyclovir were compared in enzyme kinetic experiments , using purified herpes simplex virus type 2 thymidine kinase .
C0018321
guanine
C0001367
acyclovir