アオノ リク
青野 陸
AONO RIKU
所属 生命科学部 生物工学科
職名 助教
言語種別 英語
発行・発表の年月 2012/12
形態種別 研究論文(学術雑誌)
査読 査読あり
標題 Enzymatic Characterization of AMP Phosphorylase and Ribose-1,5-Bisphosphate Isomerase Functioning in an Archaeal AMP Metabolic Pathway
執筆形態 不明
掲載誌名 JOURNAL OF BACTERIOLOGY
出版社・発行元 AMER SOC MICROBIOLOGY
巻・号・頁 194(24),6847-6855
著者・共著者 Riku Aono,Takaaki Sato,Ayumu Yano,Shosuke Yoshida,Yuichi Nishitani,Kunio Miki,Tadayuki Imanaka,Haruyuki Atomi
概要 AMP phosphorylase (AMPpase), ribose-1,5-bisphosphate (R15P) isomerase, and type III ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) have been proposed to constitute a novel pathway involved in AMP metabolism in the Archaea. Here we performed a biochemical examination of AMPpase and R15P isomerase from Thermococcus kodakarensis. R15P isomerase was specific for the alpha-anomer of R15P and did not recognize other sugar compounds. We observed that activity was extremely low with the substrate R15P alone but was dramatically activated in the presence of AMP. Using AMP-activated R15P isomerase, we reevaluated the substrate specificity of AMPpase. AMPpase exhibited phosphorylase activity toward CMP and UMP in addition to AMP. The [S]-v plot (plot of velocity versus substrate concentration) of the enzyme toward AMP was sigmoidal, with an increase in activity observed at concentrations higher than approximately 3 mM. The behavior of the two enzymes toward AMP indicates that the pathway is intrinsically designed to prevent excess degradation of intracellular AMP. We further examined the formation of 3-phosphoglycerate from AMP, CMP, and UMP in T. kodakarensis cell extracts. 3-Phosphoglycerate generation was observed from AMP alone, and from CMP or UMP in the presence of dAMP, which also activates R15P isomerase. 3-Phosphoglycerate was not formed when 2-carboxyarabinitol 1,5-bisphosphate, a Rubisco inhibitor, was added. The results strongly suggest that these enzymes are actually involved in the conversion of nucleoside monophosphates to 3-phosphoglycerate in T. kodakarensis.
DOI 10.1128/JB.01335-12
ISSNコード 00219193
PMID 23065974
PermalinkURL https://jb.asm.org/content/194/24/6847.long