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Applied Microbiology and Biotechnology

, Volume 59, Issue 1, pp 72–78 | Cite as

2-Amino-3-carboxy-1,4-naphthoquinone affects the end-product profile of bifidobacteria through the mediated oxidation of NAD(P)H

  •  S. Yamazaki
  •  T. Kaneko
  •  N. Taketomo
  •  K. Kano
  •  T. Ikeda
Original Paper

Abstract.

Glucose metabolism of bifidobacteria in the presence of 2-amino-3-carboxy-1,4-naphthoquinone (ACNQ), a specific growth stimulator for bifidobacteria, and ferricyanide (Fe(CN)6 3–) as an extracellular electron acceptor was examined using resting cells of Bifidobacterium longum and Bifidobacterium breve. NAD(P)H in the cells is oxidized by ACNQ with the aid of diaphorase activity, and reduced ACNQ donates the electron to Fe(CN)6 3–. Exogenous oxidation of NADH by the ACNQ/Fe(CN)6 3– system suppresses the endogenous lactate dehydrogenase reaction competitively, which results in the remarkable generation of pyruvate and a decrease in lactate production. In addition, a decrease in acetate generation is also observed in the presence of ACNQ and Fe(CN)6 3–. This phenomenon could not be explained in terms of the fructose-6-phosphate phosphoketolase pathway, but suggests rather that glucose is partially metabolized via the hexose monophosphate pathway. This was verified by NADP+-induced reduction of Fe(CN)6 3– in cell-free extracts in the presence of ACNQ. Effects of the ACNQ/Fe(CN)6 3– system on anaerobically harvested cells were also examined. Stoichiometric analysis of the metabolites from the pyruvate-formate lyase pathway suggests that exogenous oxidation of NADH is an efficient method to produce ATP in this pathway.

Keywords

NADH Lyase Naphthoquinone Bifidobacterium Longum Hexose Monophosphate 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Springer-Verlag 2002

Authors and Affiliations

  •  S. Yamazaki
    • 1
  •  T. Kaneko
    • 2
  •  N. Taketomo
    • 2
  •  K. Kano
    • 1
  •  T. Ikeda
    • 1
  1. 1.Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Sakyo, Kyoto 606-8502, Japan
  2. 2.Food Functionality Research Institute, Meiji Milk Products Co., Ltd., 1-21-3 Sakae, Higashimurayama, Tokyo 189-8530, Japan

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