Effect of vitamin C on the activation of β-glucosidase in Lactobacillus acidophilus GIM1.208 and the interaction between them

Abstract:

[Background] A preliminary study showed that vitamin C (VC) had a significant activation effect on the β-glucosidase (BGL) from Lactobacillus acidophilus GIM1.208. [Objective] To explore the effect of VC on BGL and the interaction between VC and BGL. [Methods] The 4-nitrophenol method, electrochemistry, Zeta potential, and nuclear magnetic resonance were employed to study the effect of VC on BGL activity and the interaction characteristics. [Results] VC exerted a significant effect on the catalytic activity of BGL, with K_m=1.167 mmol/L, and the V_max increased with the increase in VC concentration. BGL presented the highest activity when the VC concentration was 3.5%. At the VC concentration of 3.5% and a temperature below 30 ℃, the BGL activity was barely affected by temperature, and VC had a good stabilizing effect on BGL, which showed the relative activity above 90%. VC can bind to BGL, and the weak electrostatic interaction between VC and BGL facilitated the electroxidation of VC. We hypothesized that there was a hydrogen bond between the ethylene glycol branch chain in VC molecule and BGL. [Conclusion] VC can activate BGL. We studied the type and site of interaction between VC and BGL, aiming to provide a theoretical reference for the application of BGL and the efficient utilization of natural enzyme activators.