3 years ago

Hidden Antioxidative Functions of Reduced Nicotinamide Adenine Dinucleotide Coexisting with Hemoglobin

Hidden Antioxidative Functions of Reduced Nicotinamide Adenine Dinucleotide Coexisting with Hemoglobin
Magohei Yamada, Hiromi Sakai
Ferrous oxyhemoglobin (HbO2) in red blood cells (RBCs) invariably and slowly autoxidizes to form ferric methemoglobin (metHb). However, the level of metHb is always maintained below 0.5% by intracellular metHb reduction of enzymatic systems with coenzymes, such as reduced nicotinamide adenine dinucleotide (NADH), and by superoxide dismutase (SOD) and catalase (CAT), which eliminate reactive oxygen species. Unquestionably, NADH cannot reduce metHb without the corresponding enzymatic system. Our study, however, demonstrated that a high concentration of NADH (100-fold of normal level, equimolar to HbO2) retarded autoxidation of HbO2 in a highly purified Hb solution with no enzymatic system. Furthermore, an inhibitory effect of NADH on metHb formation was observed with additions of oxidants such as H2O2, NO, and NaNO2. Our mechanism assessment elucidated extremely high pseudo-CAT and pseudo-SOD activities of NADH with coexistence of HbO2, and reactivity of NADH with NO. We prepared a model of RBCs (Hb-vesicles, Hb-V) encapsulating purified HbO2 solution and NADH, but no enzymatic system within liposome. We confirmed the inhibitory effect of NADH on both autoxidation and oxidant-induced metHb formation. In addition, an intravenous administration of these Hb-Vs to rats caused significant retardation of metHb formation by approximately 50% compared to the case without NADH coencapsulation. Based on these results, we elucidated a new role of NADH, that is, antioxidative effect via interaction with Hb, in addition to its classical role as a coenzyme.

Publisher URL: http://dx.doi.org/10.1021/acschembio.7b00174

DOI: 10.1021/acschembio.7b00174

You might also like
Discover & Discuss Important Research

Keeping up-to-date with research can feel impossible, with papers being published faster than you'll ever be able to read them. That's where Researcher comes in: we're simplifying discovery and making important discussions happen. With over 19,000 sources, including peer-reviewed journals, preprints, blogs, universities, podcasts and Live events across 10 research areas, you'll never miss what's important to you. It's like social media, but better. Oh, and we should mention - it's free.

  • Download from Google Play
  • Download from App Store
  • Download from AppInChina

Researcher displays publicly available abstracts and doesn’t host any full article content. If the content is open access, we will direct clicks from the abstracts to the publisher website and display the PDF copy on our platform. Clicks to view the full text will be directed to the publisher website, where only users with subscriptions or access through their institution are able to view the full article.