Background: Human serum albumin (hSA), the major component in blood plasma, fulfills a fundamental biological role as a universal carrier and reservoir in blood plasma, tissues, and secretions. Because of essential diversity in the bound ligands, hSA was shown to possess significant structural divergence. In the first paper of this series we reported on that albumin-enriched fractions isolated from serum of glomerulonephritis (GN) patients possesses essential blue shift of intrinsic fluorescence. Identification of this component was the major goal of this study.
Material/methods: Partially purified SA preparations were isolated from blood plasma of 19 GN patients and 8 healthy donors. These preparations have been analyzed by combination of chromatographic (gel-filtration and hydrophobic sorption) and spectrofluorometric techniques.
Results: At least six different albumin enriched fractions were isolated from blood of GN patients. High molecular weight protein fraction with blue shifted intrinsic fluorescence spectrum was segregated. Higher concentration of this fraction may be responsible for higher parameter A values, which is characteristic of protein preparations from GN patients. Amino acid sequence showed that b-haptoglobin is one of the components of this fraction.
Conclusions: Combination of chromatographic methods with monitoring intrinsic fluorescence spectra of albumin-enriched fractions from blood plasma of healthy donors and GN patients represents a useful tool for the description of hSA heterogeneity and for the detection of the changes in the level of disease-related compounds. This approach is also appropriate for the isolation of individual components, different in their parameter A values, from the blood plasma.