Figure 4.

Relationships between NADH decay rates and viscosity for experiments performed at 20°C (circles), 50°C (squares), 70°C (triangles), and 90°C (diamonds). Different viscosities at a single temperature were obtained by using different concentrations of ethylene glycol (0, 10, 20, 30, 40, 50, and 60%, final concentrations). Open symbols represent control solutions without ethylene glycol. Solid symbols of increasing darkness represent increasing ethylene glycol concentrations. The solutions with different concentrations of ethylene glycol assayed at the same temperature are linked by a continuous solid line and they show the apparent trend of NADH stabilization at increasing viscosity. Solutions of equal composition are linked by a dotted line showing the effect of temperature on viscosity and NADH decay rate. Error bars are shown except when covered by solid symbols.