The acid tolerant L-arabinose isomerase from the food grade Lactobacillus sakei 23K is an attractive D-tagatose producer.
The araA gene encoding an L-arabinose isomerase (L-AI) from the psychrotrophic and food grade Lactobacillus sakei 23K was cloned, sequenced and over-expressed in Escherichia coli. The recombinant enzyme has an apparent molecular weight of nearly 220 kDa, suggesting it is a tetramer of four 54 kDa monomers. The enzyme is distinguishable from previously reported L-AIs by its high activity and stability at temperatures from 4 to 40 degrees C, and pH from 3 to 8, and by its low metal requirement of only 0.8 mM Mn(2+) and 0.8 mM Mg(2+) for its maximal activity and thermostability. Enzyme kinetic studies showed that this enzyme displays a high catalytic efficiency allowing D-galactose bioconversion rates of 20% and 36% at 10 and 45 degrees C, respectively, which are useful for commercial production of D-tagatose.
Rhimi
Moez
M
Laboratoire de BioCristallographie, Institut de Biologie et Chimie des Protéines, UMR 5086-CNRS/Université de Lyon, IFR128 BioSciences Gerland-Lyon Sud, 7 Passage du Vercors, F-69367 Lyon cedex 07, France.
Ilhammami
Rimeh
R
Bajic
Goran
G
Boudebbouze
Samira
S
Maguin
Emmanuelle
E
Haser
Richard
R
Aghajari
Nushin
N
D000143:Acids / Q000378:metabolism*; D019747:Aldose-Ketose Isomerases / Q000235:genetics / Q000378:metabolism*; D003001:Cloning, Molecular; D004795:Enzyme Stability / Q000187:drug effects; D005516:Food Microbiology; D005690:Galactose / Q000378:metabolism; D005798:Genes, Bacterial / Q000235:genetics; D006601:Hexoses / Q000096:biosynthesis*; D006863:Hydrogen-Ion Concentration / Q000187:drug effects; D007477:Ions; D007700:Kinetics; D007778:Lactobacillus / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics; D008670:Metals / Q000494:pharmacology; D011994:Recombinant Proteins / Q000302:isolation & purification; D013696:Temperature
D000143:Acids; D006601:Hexoses; D007477:Ions; D008670:Metals; D011994:Recombinant Proteins; D019747:Aldose-Ketose Isomerases; C019715:L-arabinose isomerase; C030192:tagatose; D005690:Galactose