Cloning, purification and characterization of an NAD-Dependent D-Arabitol dehydrogenase from acetic acid bacterium, Acetobacter suboxydans.
D-Xylulose-forming D-arabitol dehydrogenase (aArDH) is a key enzyme in the bio-conversion of D-arabitol to xylitol. In this study, we cloned the NAD-dependent D-xylulose-forming D-arabitol dehydrogenase gene from an acetic acid bacterium, Acetobacter suboxydans sp. The enzyme was purified from A. suboxydans sp. and was heterogeneously expressed in Escherichia coli. The native or recombinant enzyme was preferred NAD(H) to NADP(H) as coenzyme. The active recombinant aArDH expressed in E. coli is a homodimer, whereas the native aArDH in A. suboxydans is a homotetramer. On SDS-PAGE, the recombinant and native aArDH give one protein band at the position corresponding to 28 kDa. The optimum pH of polyol oxidation and ketone reduction is found to be pH 8.5 and 5.5 respectively. The highest reaction rate is observed when D-arabitol is used as the substrate (K (m) = 4.5 mM) and the product is determined to be D-xylulose by HPLC analysis.
Cheng
Hairong
H
Laboratory of Microbial Metabolism and School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, 200194, Shanghai, China. chrqrq@sjtu.edu.cn
Li
Zilong
Z
Jiang
Ning
N
Deng
Zixin
Z
D000091:Acetobacter / Q000201:enzymology*; D000595:Amino Acid Sequence; D003001:Cloning, Molecular; D004492:Edetic Acid / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D008670:Metals / Q000378:metabolism; D009243:NAD / Q000378:metabolism; D010084:Oxidation-Reduction; D013379:Substrate Specificity; D013401:Sugar Alcohol Dehydrogenases / Q000235:genetics* / Q000302:isolation & purification* / Q000378:metabolism; D013696:Temperature
D008670:Metals; D009243:NAD; D004492:Edetic Acid; D013401:Sugar Alcohol Dehydrogenases; C022751:D-arabinitol dehydrogenase