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Photoregeneration of NADH Using Carbon-Containing TiO 2

2005; American Chemical Society; Volume: 44; Issue: 12 Linguagem: Inglês

10.1021/ie049155w

1520-5045

Zhongyi Jiang, Chenqiu Lü, Hong Wu,

Electrochemical sensors and biosensors

A novel photochemical approach for NADH regeneration, which employs visible light as a light source, carbon-containing TiO2, and [Cp*Rh(bpy)(H2O)]2+ as a catalyst, has been developed here. The carbon-containing TiO2 has a strong absorption toward visible light. [Cp*Rh(bpy)(H2O)]2+ shows high activity and selectivity toward 1,4-NADH. In the photoregeneration of NADH, the conversion is low and only achieves 25.83% at 31 °C and pH 6.5 when using H2O as an electron donor. While under the same conditions using mercaptoethanol, the conversion achieves 74.30% and even reaches 94.29% in the presence of H2. Lower pH and higher temperature result in higher conversion and a higher reaction rate. The influence of the initial concentration of [Cp*Rh(bpy)(H2O)]2+ on NADH photoregeneration is much greater than that of the initial concentration of NAD+. The optimum conditions for NADH photoregeneration are determined to be a pH of 6.0, 37 °C, a NAD+ initial concentration of 0.2 mM, and a [Cp*Rh(bpy)(H2O)]2+ initial concentration of 0.3∼0.5 mM. The conversion achieves 63.98% under optimum conditions.