title: Expression and characterization of fumarase (FUMR) from Rhizopus oryzae.
abstract: Fumarase catalyzes the reversible hydration of fumarate to l-malate in Rhizopus oryzae. A recombinant pET22b-fumR harboring a fumarase gene (fumR) from R. oryzae was constructed for high level expression in E. coli BL21 (DE3). The FUMR activity was optimal at 30°C and pH 7.2. The enzyme was stable below 45°C and at pH 3.0-9.0. No effects of Zn(2+), Fe(2+), or EDTA were observed on enzyme activity. A slight inhibition of FUMR activity was seen with Mg(2+), while Ca(2+) had a small stimulatory effect. The K(m) for l-malic acid and fumaric acid were 0.46 mM and 3.07 mM, respectively. The activity of FUMR catalyzing hydration of fumarate to l-malate was completely inhibited by 2mM fumaric acid. The unique enzymatic properties suggested that overexpression of FUMR could enhance fumaric acid accumulation in R. oryzae.
authors.affiliation: State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing University of Technology, No. 5 Xinmofan Road, Nanjing 210009, PR China.
authors.forename: Ping
authors.initials: P
authors.lastname: Song
authors.forename: Shuang
authors.initials: S
authors.lastname: Li
authors.forename: Yueyue
authors.initials: Y
authors.lastname: Ding
authors.forename: Qing
authors.initials: Q
authors.lastname: Xu
authors.forename: He
authors.initials: H
authors.lastname: Huang
mesh_terms: D004795:Enzyme Stability; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D005649:Fumarate Hydratase / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D005656:Fungal Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D015870:Gene Expression; D007700:Kinetics; D012233:Rhizopus / Q000737:chemistry / Q000201:enzymology* / Q000235:genetics
chemical_list: D005656:Fungal Proteins; D005649:Fumarate Hydratase