Unraveling the Effects of Hexametaphosphate: Insights into Trypsin Aggregation and Structural Reversal.

Elevated serum phosphate levels have been linked to increased mortality rates. This study investigated the effect of millimolar (mM) concentrations of sodium hexametaphosphate (SHMP) on trypsin's aggregation and structural stability at intestinal pH levels. We used various spectroscopic and microscopic techniques to investigate the structural changes of trypsin aggregates. Turbidity and light scattering results revealed that trypsin aggregates began to solubilize at SHMP concentrations above 1 mM, with maximum solubilization observed at 6 mM SHMP. Intrinsic, thioflavin T (ThT) fluorescence, and far-UV CD spectra indicated that trypsin amorphous aggregates turn into native-like structures in the presence of 6 mM SHMP. Transmission electron microscope (TEM) imaging also showed the disappearance of amorphous aggregates at higher SHMP concentrations. This study showed that higher SHMP concentrations solubilized the trypsin aggregates and induced a native-like conformation. These findings highlighted that SHMP could be a good protein aggregate solubilizer, with future applications in inclusion body solubilization and protein refolding.