The selectivity of copper-induced protein aggregates in serum.

CHRISTIAN SAPORITO; MARÍA LAURA FACCIO; MARISA GABRIELA REPETTO

CIUDAD AUTONOMA BUENOS AIRES

Congreso; 66º Reunión Anual de la Sociedad Argentina de Investigación Clínica; 2021

Sociedad Argentina de Investigación Clínica

Copper (Cu) reactivity is largely based on its ability to participate in redox chemistry and nature has employed it in the active site of different enzymes. Cu-induced damage has also been related to redox reactions. However, no antioxidant therapy has been approved in Cu-related pathologies and Cu-mediated non-redox reactions remain extensively unexplored in such diseases. Previously, we have shown the relevance of Cu-induced protein aggregation over oxidative damage and found that Cu aggregates albumin (Alb) at high concentrations. We speculated that the heterogeneous group of proteins in serum should comprise proteins with higher propensity to aggregation. Objective: To assess the selectivity of Cu-induced protein aggregation in serum. Methods: Optic density (OD), SDS-PAGE and proteinogram in cellulose acetate. Results: OD kinetic analysis of albumin (Alb), serum or plasma exposed to Cu was performed. Protein aggregation from healthy rat serum occurred at lower Cu concentrations (less than 100 µM) than Alb. No significant differences were observed between serum and plasma. The aggregation of serum proteins is dependent of Cu but independent of protein concentration. The aggregation curve of serum is flatter than Alb, likely due to the heterogeneous group of proteins present in serum. With SDS-page we determined that serum aggregates exposed to low concentrations of Cu are enriched in high molecular weight proteins and some low molecular weight proteins while very poor in Alb. The proteinogram of serum pellet obtained after Cu-induced aggregation showed enrichment in gamma-globulin fraction (p