کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
681898 | 888970 | 2010 | 7 صفحه PDF | دانلود رایگان |
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 °C, and pH from 3 to 8, and by its low metal requirement of only 0.8 mM Mn2+ and 0.8 mM Mg2+ 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 °C, respectively, which are useful for commercial production of d-tagatose.
Journal: Bioresource Technology - Volume 101, Issue 23, December 2010, Pages 9171–9177