Abstract
Gelsolin is an actin monomer binding and filament severing protein synthesized in plasma and cytoplasmic forms differing by an N‐terminal amino acid extension and a disulfide bond between Cys‐188 and Cys‐201. To determine whether this bond altered gelsolin regulation or function, oxidized and reduced plasma gelsolins were assayed for severing, monomer binding and nucleation activity at a variety of rate‐limiting calcium concentrations. The results indicate that the disulfide bond in domain 2 of gelsolin influences the transmission of information from C‐terminal regulatory sites to functional sites in the N‐terminus.