Study on the mechanism underlying Al-induced hepatotoxicity based on the identification of the Al-binding proteins in liver

Comparative study of aluminum speciation on brain-type creatine kinase: Enzyme kinetic, molecular docking, cellular experiment, and mouse model study

Brain-type Creatine kinase (CK-BB), which has a high affinity for Aluminum (Al), and its abnormality is closely related to neurodegenerative diseases. In this study, the comparative effect of Al speciation on the bioactivity of CK-BB has been studied by the inhibition kinetics method, molecular docking, cellular experiment, and mouse model study. Results showed that the half-inhibitory concentration of AlCl₃ was 0.67 mM, while Al(mal)₃ was 3.81 mM. Fluorescence spectra showed that Al(mal)₃ had a more substantial effect on the endogenous fluorescence of CK-BB than AlCl₃. Molecular docking showed that AlCl₃ was closer to the active site of CK-BB. C6 cells were used to explore the enzyme activity and intracellular distribution of CK-BB by AlCl₃ or Al(mal)₃. AlCl₃ treatment may directly affect CK-BB activity and cause insufficient local ATP supply in cells which affected the formation of F-actin and cell morphology. The change in the hydrophobicity of CK-BB induced by Al(mal)₃ affected the movement of CK-BB, which subsequently activated thecytochrome C (Cyt C)/Caspase 9/Caspase 3 pathway. Similar results have been found in vivo experiments. This study demonstrated that interaction between Al and CK-BB might be related to the process of Al-induced energy metabolism disorders, in which the Al speciation revealed differentiated toxicity mechanisms.

Effects of different food ingredients on the color and absorption spectrum of carminic acid and carminic aluminum lake

In this study, three foodstuffs (surimi, minced meat, and milk) were dyed with carminic acid and carminic aluminum lake. The effects of protein, metal ions, and food additives on the color of carminic acid and carminic aluminum lake were investigated. After being dyed by carminic acid, the colors of surimi, minced meat, and milk were light purple, red, and gray-green, respectively. When using carminic aluminum lake, surimi and milk were magenta, and minced meat was red. Regarding the carminic acid solution, the presence of myofibrillar protein (MFP), whey protein isolate (WPI), and soy protein isolate (SPI) turned it red by changing the pH, while the presence of casein made it orange. The carminic aluminum lake solution turned magenta in all four cases, which were not affected by protein. The color of carminic acid and carminic aluminum lake was significantly affected by 0.001-0.1 mol/L Fe3+, 0.001-0.1 mol/L Fe2+, 0.001-0.1 mol/L Cu2+, and 0.1 mol/L Ca2+, limiting their application in iron-, copper-, and high-calcium foods. The color of carminic acid was changed to yellow by 0.01%-1% sodium nitrite, but 0.01%-1% ascorbic acid and 0.01%-0.1% monascus color did not significantly affect the color of either carminic acid or carminic aluminum lake. This paper provides a reference for the application of carminic acid and carminic aluminum lake in food science.