title: Nucleosides. 5. Synthesis of guanine and formycin B derivatives as potential inhibitors of purine nucleoside phosphorylase.
abstract: In an effort to develop potent human purine nucleoside phosphorylase (PNP) inhibitors as immunosuppressive and chemotherapeutic agents, several 8-aminoguanine derivatives were synthesized and evaluated as potential PNP inhibitors. These studies were designed to investigate the hydrophobic effect of a substituent on the N-9 of the purine heterocycle and/or the C-5' positions. Compounds such as 8-aminoguanosine, guanosine, formycin B, and 8-aminoacyclovir containing a p-(fluorosulfonyl)benzoyl moiety were synthesized. The affinity of these compounds to erythrocytic PNP was determined and none of these compounds showed a better affinity than those of the parent compounds. However, we found that the effect of hydrophobicity at the N-9 and the C-5' positions might play an important role in binding to the active site of PNP. Thus, 8-amino-5'-deoxy-5'-(phenylthio)guanosine (19) was found to be the best inhibitor in this series of compounds with a Ki = 0.45 microM.
authors: Medical Laboratories, National Defense Medical Center, Taipei, Taiwan, ROC.
authors: J W
authors: JW
authors: Chern
authors: H Y
authors: HY
authors: Lee
authors: C S
authors: CS
authors: Chen
authors: D S
authors: DS
authors: Shewach
authors: P E
authors: PE
authors: Daddona
authors: L B
authors: LB
authors: Townsend
mesh_terms: D001665:Binding Sites; D005573:Formycins / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D006147:Guanine / Q000031:analogs & derivatives* / Q000737:chemistry / Q000494:pharmacology; D006801:Humans; D007700:Kinetics; D011683:Purine-Nucleoside Phosphorylase / Q000037:antagonists & inhibitors* / Q000378:metabolism; D013329:Structure-Activity Relationship
chemical_list: D005573:Formycins; C033495:8-aminoguanine; D006147:Guanine; D011683:Purine-Nucleoside Phosphorylase