Purification and characterization of an inhibitor protein with cytochalasin-like acitvity from bovine adrenal medulla

A protein preparation with cytochalasin-like activity has been obtained from bovine adrenal medulla. Analysis by electrophoresis in SDS-polyacrylamide gels and chromatography in a Sephacryl S-200 column indicated that the inhibitor activity coincided with a 90 000 dalton polypeptide. The inhibitor decreased high-affinity binding of ³H]cytochalasin B to actin nuclei, apparently by competing with the drug for thesame binding site. At substoichometric levels, the inhibitor had a potent effect on actin filament elongation and on actin-dependent gelation of cell extracts in vitro. These results suggest that the inhibitor may be involved in the control of actin filament assembly and interaction in the adrenal medulla.