Properties and primary structure of a thermostable L-malate dehydrogenase from Archaeoglobus fulgidus.
A thermostable l-malate dehydrogenase from the hyperthermophilic sulfate-reducing archaeon Archaeoglobus fulgidus was isolated and characterized, and its gene was cloned and sequenced. The enzyme is a homodimer with a molecular mass of 70 kDa and catalyzes preferentially the reduction of oxaloacetic acid with NADH. A. fulgidus L-malate dehydrogenase was stable for 5 h at 90 degrees C, and the half-life at 101 degrees C was 80 min. Thus, A. fulgidus L-malate dehydrogenase is the most thermostable L-malate dehydrogenase characterized to date. Addition of K2HPO4 (1 M) increased the thermal stability by 40%. The primary structure shows a high similarity to L-lactate dehydrogenase from Thermotoga maritima and gram-positive bacteria, and to L-malate dehydrogenase from the archaeon Haloarcula marismortui and other L-lactate-dehydrogenase-like L-malate dehydrogenases.
Langelandsvik
A S
AS
Department of Microbiology, University of Bergen, Jahnebakken 5, N-5020 Bergen, Norway.
Steen
I H
IH
Birkeland
N K
NK
Lien
T
T
D000595:Amino Acid Sequence; D001105:Archaea / Q000201:enzymology* / Q000235:genetics; D001483:Base Sequence; D003001:Cloning, Molecular; D006361:Heating; D008291:Malate Dehydrogenase / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism; D008969:Molecular Sequence Data; D009243:NAD / Q000378:metabolism; D010071:Oxaloacetates / Q000378:metabolism; D010710:Phosphates / Q000378:metabolism; D010802:Phylogeny; D017680:Potassium Compounds / Q000378:metabolism; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid
D010071:Oxaloacetates; D010710:Phosphates; D017680:Potassium Compounds; D009243:NAD; C013216:potassium phosphate; D008291:Malate Dehydrogenase