The oxidative modification of albumin by hydrochlorous acid and the relationship between the oxidized HSA and AOPPs / 中华肾脏病杂志

ABSTRACT

Objective To study the effect of oxidative modification of hydrochlorous acid (HOCl) on human serum albumin (HSA) and the relationship between the AOPPs and HOCl-treated HSA. Methods Purified HSA (60 mg/ml) was treated with HOCl (0, 1, 5, 10, 20, 30, 40, 50 and 60 mmol/L). Size-exclusion chromatography was applied to estimate molecular weights of oxidized products of HSA by HOCl and spectrum scan from 190 nm -400 nm was performed to observe the spectrum characteristics of all variants of HSA. Results Major products of HSA after exposure to HOC1 were dimer and hexmer of HSA. The first-order process could be employed to describe the oxidative dynamics of monomer and dimer of HSA oxidized by HOCl. To AOPPs formation mediated by oxidant was identified as pseudo first-order reaction. However, formation hexmer was much in accordance with second-order reaction. Hexmer was also a major contributor to AOPPs in all types of modified HSA. Spectral analysis showed that red shift of absorbance maximum of polymers of HSA occurred, suggesting that a possibility that polymers of HSA were cross linked by tyrosine residues in protein. Conclusions Protein aggregation is primary consequence of HSA after its exposure to HOCl. Hexmer of HSA is the major contributor to AOPPs.