News Column

Studies from Shanghai Jiao-Tong University in the Area of Sugar Alcohols Described

May 30, 2014



By a News Reporter-Staff News Editor at Health & Medicine Week -- Investigators publish new report on Sugar Alcohols. According to news reporting out of Shanghai, People's Republic of China, by NewsRx editors, research stated, "Glycerol dehydrogenase (GDH) is an important polyol dehydrogenase for glycerol metabolism in diverse microorganisms and for value-added utilization of glycerol in the industry. Two GDHs from Klebsiella pneumoniae, DhaD and GldA, were expressed in Escherichia coli, purified and characterized for substrate specificity and kinetic parameters."

Our news journalists obtained a quote from the research from Shanghai Jiao-Tong University, "Both DhaD and GldA could catalyze the interconversion of (3R)-acetoin/(2R,3R)-2,3-butanediol or (3S)-acetoin/meso-2,3-butanediol, in addition to glycerol oxidation. Although purified GldA appeared more active than DhaD, in vivo inactivation and quantitation of their respective mRNAs indicate that dhaD is highly induced by glycerol and plays a dual role in glycerol metabolism and 2,3-butanediol formation. Complementation in K. pneumoniae further confirmed the dual role of DhaD. Promiscuity of DhaD may have vital physiological consequences for K. pneumoniae growing on glycerol, which include balancing the intracellular NADH/NAD(+) ratio, preventing acidification, and storing carbon and energy. According to the kinetic response of DhaD to modified NADH concentrations, DhaD appears to show positive homotropic interaction with NADH, suggesting that the physiological role could be regulated by intracellular NADH levels. The co-existence of two functional GDH enzymes might be due to a gene duplication event. We propose that whereas DhaD is specialized for glycerol utilization, GldA plays a role in backup compensation and can turn into a more proficient catalyst to promote a survival advantage to the organism."

According to the news editors, the research concluded: "Revelation of the dual role of DhaD could further the understanding of mechanisms responsible for enzyme evolution through promiscuity, and guide metabolic engineering methods of glycerol metabolism."

For more information on this research see: Glycerol dehydrogenase plays a dual role in glycerol metabolism and 2,3-butanediol formation in Klebsiella pneumoniae. Journal of Biological Chemistry, 2014;289(9):6080-90. (American Society for Biochemistry and Molecular Biology - www.asbmb.org; Journal of Biological Chemistry - www.jbc.org/)

Our news journalists report that additional information may be obtained by contacting Y. Wang, From the State Key Laboratory of Microbial Metabolism and School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, People's Republic of China. Additional authors for this research include F. Tao and P. Xu (see also Sugar Alcohols).

Keywords for this news article include: Asia, Shanghai, Glycerol, Metabolism, Dehydrogenase, Sugar Alcohols, Enterobacteriaceae, Enzymes and Coenzymes, Klebsiella pneumoniae, Gram Negative Bacteria, People's Republic of China.

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Source: Health & Medicine Week