title: [Characterization of a malic enzyme isoform V from Mucor circinelloides].
abstract: OBJECTIVE
  We aimed at characterizing a malic enzyme isoform V from Mucor circinelloides.
  
  
  METHODS
  me1 gene encoding malic enzyme isoform V was amplified and cloned into expression vector pET28a. High-purity recombinant protein BLME1 was obtained by affinity chromatography using. Ni-NTA column and characterized subsequently.
  
  
  RESULTS
  The optimum conditions were pH at 8.0 and temperature at 33 degrees C. Under optimum conditions, BLME1 activity achieved 92.8 U/mg. The K(m) for L-malate and NADP+ were 0.74960 ± 0.06120 mmol/L and 0.22070 ± 0.01810 mmol/L, the V(max) for L-malate and NADP+ were 72.820 ± 1.077 U/mg and 86.110 ± 1.665 U/mg, respectively. In addition, ions played important roles in BLME1 activity; several ions such as Mn2+, Mg2+, Co2+, Ni2+ could activate BLME1, whereas Ca2+, Cu2+ could be used as inhibitors. Additionally, the metabolic intermediates such as oxaloacetic acid and α-ketoglutaric acid inhibited the activity of BLME1, whereas succinic acid activated it.
  
  
  CONCLUSIONS
  A malic enzyme isoform V from Mucor circinelloides was characterized, providing the references for further studies on this enzyme.
authors.forename: Yingtong
authors.initials: Y
authors.lastname: Zhang
authors.forename: Haiqin
authors.initials: H
authors.lastname: Chen
authors.forename: Yuanda
authors.initials: Y
authors.lastname: Song
authors.forename: Hao
authors.initials: H
authors.lastname: Zhang
authors.forename: Yongquan
authors.initials: Y
authors.lastname: Chen
authors.forename: Wei
authors.initials: W
authors.lastname: Chen
mesh_terms: D020816:Amino Acid Motifs; D004795:Enzyme Stability; D005656:Fungal Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008291:Malate Dehydrogenase / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D008958:Models, Molecular; D009089:Mucor / Q000737:chemistry / Q000201:enzymology* / Q000235:genetics; D020033:Protein Isoforms / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D013696:Temperature
chemical_list: D005656:Fungal Proteins; D020033:Protein Isoforms; D008291:Malate Dehydrogenase; C030574:malate dehydrogenase (decarboxylating)