First Immunoassay for Measuring Isoaspartate in Human Serum Albumin

Isoaspartate (isoAsp) is a damaging amino acid residue formed in proteins mostly as a result of spontaneous deamidation of asparaginyl residues. An association has been found between isoAsp in human serum albumin (HSA) and Alzheimer's disease (AD). Here we report on a novel monoclonal antibody (mAb) 1A3 with excellent specificity to isoAsp in the functionally important domain of HSA. Based on 1A3 mAb, an indirect enzyme-linked immunosorbent assay (ELISA) was developed, and the isoAsp occupancy in 100 healthy plasma samples was quantified for the first time, providing the average value of (0.74 & PLUSMN; 0.13)%. These results suggest potential of isoAsp measurements for supplementary AD diagnostics as well as for assessing the freshness of stored donor blood and its suitability for transfusion.

Automated summary

A novel monoclonal antibody 1A3 with excellent specificity to isoAsp in the functionally important domain of HSA was developed, leading to the quantification of isoAsp occupancy in 100 healthy plasma samples. These results suggest the potential of isoAsp measurements for supplementary AD diagnostics and assessing the freshness of stored donor blood for transfusion suitability.