The yjjN of E. coli codes for an l-galactonate dehydrogenase and can be used for quantification of l-galactonate and l-gulonate.

Kuivanen, Joosu; Richard, Peter

Escherichia coli is able to utilize l-galactonate as a sole carbon source. A metabolic pathway for l-galactonate catabolism is described in E. coli, and it is known to be interconnected with d-galacturonate metabolism. The corresponding gene encoding the first enzyme in the l-galactonate pathway, l-galactonate-5-dehydrogenase, was suggested to be yjjN. However, l-galactonate dehydrogenase activity was never demonstrated with the yjjN gene product. Here, we show that YjjN is indeed an l-galactonate dehydrogenase having activity also for l-gulonate. The K and k for l-galactonate were 19.5 ± 0.6 mM and 0.51 ± 0.03 s, respectively. In addition, YjjN was applied for a quantitative detection of the both of these substances in a coupled assay. The detection limits for l-galactonate and l-gulonate were 1.65 and 10 μM, respectively.

ESCHERICHIA coli; DEHYDROGENASES; METABOLISM; CARBON; ENZYMES

Applied Biochemistry & Biotechnology, 2014, Vol 173, Issue 7, p1829

0273-2289

Academic Journal

10.1007/s12010-014-0969-0