A cDNA library was constructed using kernels of early mature barley (possessing eam10). A S-AdenosylMethionine Syntase (HvSAMS, Hordeum vulgare S-AdenosylMethionine Syntase) gene that was differentially expressed in the grain development of 3 days after fertilization was isolated and its tissue/developmental specific expression was analyzed. The cDNA encoding HvSAMS contained a 1185 bp open reading frame (ORF) that encoded 394 amino acids. Southern blot analysis showed at least 2 copies were existed in barley. Transcript levels of HvSAMS mRNA were highest at -6, -3, 0 DAF (Days After Fertilization) and in grain tissues. The expression of HvSAMS was increased in leaves in response to abiotic stresses such as salt as well as to hormones such as ABA, GA3, ABA+GA3, and spermidine. In wounding treatment, the HvSAMS mRNA was highest at 3h and then decreased. It's expression was high at 24h after ethylene/wounding treatment. Coding region of HvSAMS was cloned in the protein expression vector(pET32) and transformed into the host cells(BL21). Translational products of HvSAMS were successfully identified through 1D SDS-PAGE after induction with IPTG. Hybridization with a anti-HIS antibody at the expected size was obtained (52 kDa). In order to identify proteins that interacted with HvSAMS, a yeast two hybridization library [Transformants : 4.48 X 106 cell/ml (SD/Leu^-/Trp^-)] was also constructed. The initial screening identified 21 potential HvSAMS-interacting clones and finally 4 interacting clones were selected. Two clones from the selected clones showed perfect identity and contained one PKC (Protein Kinase C) motif and was designated as HvVDAC (Hordeum vulgare Voltage Dependent Anion Channels). HvVDAC contained a 828 bp ORF that encoded 275 amino acids, and presented as single copy in barley. HvVDAC mRNA were highly detected early stage of fertilized reproductive organs. - This work was supported by a grant from BioGreen 21 Program, RDA, Republic of Korea. - Contact (YW Seo): seoag@korea.ac.kr