The promotion of self‐association of horse‐heart cytochrome c by hexametaphosphate anions

Publisher Website
Google Scholar
Abstract
In the presence of the highly charged hexametaphosphate anion, horse heart cytochrome c aggregates to form stable protein complexes. The formation of protein aggregates has been detected by high‐resolution 1H‐NMR spectroscopy from an increase in the linewidth of resolved ferricytochrome c resonances with hexametaphosphate concentration. Alternatively, analytical ultracentrifugation reveals protein association from the increase in apparent sedimentation coefficients of cytochrome c in the presence of equimolar hexametaphosphate. Protein aggregation is dependent on the concentration of background electrolyte since in the range 10–150 mM sodium cacodylate alternative stabilisation of dimeric and trimeric complexes was observed by both NMR and analytical ultracentrifugation. A model is proposed for the mechanism of protein aggregation caused by polyphosphate binding to the surface of cytochrome c.