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Biomaterials and Biomedical Engineering Volume 3, Number 1, March 2016 , pages 37-46 DOI: https://doi.org/10.12989/bme.2016.3.1.037 |
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Enhanced stability of NADH/dehydrogenase mixture system by water-soluble phospholipid polymers |
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Kyoko Fukazawa and Kazuhiko Ishihara
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| Abstract | ||
| To maintain activity in a coenzyme/enzyme mixture system, such as β-nicotinamide adenine dinucleotide (NADH)/dehydrogenase, the water-soluble 2-methacryloyloxyethyl phosphorylcholine (MPC) polymers as an additive were synthesized and investigated for their stabilizing function. The inhibitor for the NADH/dehydrogenase reaction was spontaneously formed when the NADH was stored in the dehydrogenase solution. Therefore, we hypothesized that if the additive polymer could interact with an inhibitor without any adverse effect on the dehydrogenase, the activity in the NADH/dehydrogenase mixture could be maintained. We selected lactose dehydrogenase (LDH) as the enzyme, and the NADH was dissolved and incubated at 37°C in the LDH solution containing the polymers. The phospholipid polymers used in this study were poly(MPC) (PMPC), poly(MPC-co-3-trimethylammonium-2-hydroxypropyl methacrylate chloride) (PMQ) and poly[MPC-co-potassium 3-methacryloyloxypropyl sulfonate (MSO3)] (PMMSO3). The poly(MSO3) was used as a reference. For the PMQ and PMSO3 aqueous solutions, the activity of the NADH/LDH mixture system decreased with incubation time as the same level or lower than that in the Tris buffered solution in the absence of the polymers. However, for the poly(MPC-co-MSO3) (PMMSO3) aqueous solution, the activity of the NADH/LDH mixed system was six times higher than that in the buffered solution even after a 3-days incubation. The LDH activity was 1.5-1.8 times higher in the presence of the PMMSO3 compared with that in the PMSO3 solution. The mixture of two polymers, poly(MPC) and poly(MSO3), did not produce any stabilization. Thus, both the MPC and MSO3 units in the polymer chain had important and cooperative effects for stabilizing the NADH/LDH mixture. | ||
| Key Words | ||
| 2-methacryloyloxyethyl phosphorylcholine (MPC) polymer; charged polymers; polymeric additive; NADH/LDH mixture system; stabilization | ||
| Address | ||
| Kyoko Fukazawa and Kazuhiko Ishihara: Department of Materials Engineering, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku,Tokyo 113-8656, Japan Kazuhiko Ishihara: Department of Bioengineering, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-8656, Japan | ||
