Abstract: The crystal structure of the complex of S-adenosylmethionine methyl ester with h?doMetDC F223A, a mutant where the stacking of the aromatic rings of F7, adenine and F223 would be eliminated. The structure of this mutant with the ester shows that the ligand still maintains a syn conformation aided by pi-pi interactions to F7, hydrogen bonds to the backbone of Glu67, and electrostatic interactions. Several series of AdoMet substrate analogues with a variety of substituents at the 8 position of adenine were synthesized and analyzed for their ability to inhibit hAdoMetDC. To understand these results, virtual modeling of the enzyme inhibitor complexes and the crystal structures of human AdoMetDC with 5?-deoxy-5?-[N-methyl-N-[2-(aminooxy)ethyl]amino-8-methyl]adenosine (MAOEMA) and 5?-deoxy-5?-[N-methyl-N-[4-(aminooxy)butyl]amino-8-ethyl]adenosine (MAOBEA) at the active site have been determined experimentally.

Abstract: The specification discloses the compounds of formula I ##STR1## wherein (a) --CH.sub.2 Ar represents ##STR2## in which R.sub.1 represents hydrogen, halogen, C.sub.1 -C.sub.3 -alkyl, C.sub.1 -C.sub.3 -alkoxy, benzyloxy, hydroxy or trifluoromethyl; and R.sub.2 represents hydrogen, halogen, C.sub.1 -C.sub.3 -alkyl, C.sub.1 -C.sub.3 -alkoxy, benzyloxy, hydroxy or trifluoromethyl; provided that R.sub.2 represents hydrogen or C.sub.1 -C.sub.3 -alkyl if R.sub.1 represents trifluoromethyl, or that R.sub.1 represents hydrogen or C.sub.1 -C.sub.3 -alkyl if R.sub.2 represents trifluoromethyl; or(b) --CH.sub.2 Ar represents ##STR3## in which X represents sulfur or oxygen and in which attachment to the thiophene or furan ring is at the 2- or 3-position; and tautomers thereof; as purine nucleoside phosphorylase inhibitors.

Abstract: The specification discloses the compounds of formula I ##STR1## wherein (a) --CH.sub.2 Ar represents ##STR2## in which R.sub.1 represents hydrogen, halogen, C.sub.1 -C.sub.3 -alkyl, C.sub.1 -C.sub.3 -alkoxy, benzyloxy, hydroxy or trifluoromethyl; and R.sub.2 represents hydrogen, halogen, C.sub.1 -C.sub.3 -alkyl, C.sub.1 -C.sub.3 -alkoxy, benzyloxy, hydroxy or trifluoromethyl; provided that R.sub.2 represents hydrogen or C.sub.1 -C.sub.3 -alkyl if R.sub.1 represents trifluoromethyl, or that R.sub.1 represents hydrogen or C.sub.1 -C.sub.3 -alkyl if R.sub.2 represents trifluoromethyl; or(b) --CH.sub.2 Ar represents ##STR3## in which X represents sulfur or oxygen and in which attachment to the thiophene or furan ring is at the 2- or 3-position; and tautomers thereof; as purine nucleoside phosphorylase inhibitors.