3-Deazaadenosine is an inhibitor of S-adenosylhomocysteine hydrolase, with a Ki of 3.9 µM. 3-Deazaadenosine shows anti-HIV effect, and inhibits p24 antigen in peripheral blood mononuclear (PBMCs) cells infected with HIV-1 isolates (A012 and A018) with IC50s of 0.15 and 0.20 µM, respectively. 3-Deazaadenosine (1-100 µM) inhibits LPS-induced expression of TNF-α mRNA, increases DNA binding activity of NF-κB, and causes proteolytic degradation of IκBα, but Not IκBβ in RAW 264.7 cells. 3-Deazaadenosine (100 µM) enhances nuclear translocation of NF-κB, but blocks LPS-induced NF-κB transcriptional activity, and such inhibition is augmented by the addition of homocysteine. 3-Deazaadenosine (50, 100 µM) dose-dependently inhibits the phosphorylation of Raf and ERK, protein-dependent kinase 1, protein kinase B (Akt), and forkhead transcription factor FoxO1a. 3-Deazaadenosine (50 µM) suppresses vascular smooth muscle cell (VSMC) proliferation via interfering with Ras signaling.