Non-thermal Effects of 0.1 THz Radiation on Intestinal Alkaline Phosphatase Activity and Conformation

Alkaline phosphatase (ALP) plays an integral role in the metabolism of liver and development of the skeleton in humans. To date, the interactions between different-duration terahertz (THz) radiation and ALP activities, as well as the influence mechanism are still unclear. In this study, by using the para-nitro-phenyl-phosphate (pNPP) method, we detected changes in ALP activities during 40-minute THz radiation (0.1 THz, 13 mW/cm2). We found that the activity of ALP decreased in the first 25 minutes, and subsequently increased in the later 15 minutes. Compared with the activity of ALP being heated, the results suggested that short-term terahertz radiation induced a decrease in enzyme activity through the non-thermal mechanism. In order to explore the non-thermal effects of THz radiation on ALP, we focused on the impacts of 0.1 THz radiation for 20 minutes on the activity of ALP in different concentrations. The results revealed that the activity of ALP decreased significantly after exposure to THz radiation. In addition, it could be deduced from fluorescence, ultraviolet-visible (UV-vis), and THz spectra results that THz radiation has induced changes in ALP structures. In conclusion, our studies unlocked non-thermal interactions between THz radiation and ALP, as well as suggested that THz spectroscopy was a promising technique to distinguish ALP structures.