AIM: To model the three-dimensional structure and investigatethe interaction mechanism ofthe proprotein convertase furin/kexin and their inhibitors (eglin c mutants). METHODS: The three-dimensional complex structures of furin/ kexin with its inhibitors, eglin c mutants, were generated by modeller program using the newly published X-ray crystallographical structures of mouse furin and yeast kexin as templates. The electrostatic interaction energy of each complex was calculated and the results were compared with the experimentally determined inhibition con- stants to find the correlation between them. RESULTS: High quality models of furin/kexin-eglin c mutants were obtained and used for calculation of the electrostatic interaction energies between the proteases and their inhibitors. The calculated electrostaticenergies of interaction showeda linear correlation to the experimental inhibition constants. CONCLUSION: The modeled structures give good explanations of the specificity of eglin c mutants to furin/ kexin. The electrostatic interactions play important roles in inhibitory activity of eglin c mutants to furin/kexin. The results presented here provided quantitative structural and functional information concerning the role of the charge- charge interactions in the binding of furin/kexin and their inhibitors. AIM: To model the three-dimensional structure and investigate the interaction mechanism of the proprotein convertase furin / kexin and their inhibitors (eglin c mutants). METHODS: The three-dimensional complex structures of furin / kexin with its inhibitors, eglin c mutants, were generated by modeller program using the newly published X-ray crystallographical structures of mouse furin and yeast kexin as templates. The electrostatic interaction energy of each complex was calculated and the results were compared with the experimentally determined determined assay con- stants to find the correlation between them. RESULTS: High quality models of furin / kexin-eglin c mutants were obtained and used for calculation of the electrostatic interaction energies between the proteases and their inhibitors. The calculated electrostaticegiesgies of interaction showeda linear correlation to the experimental inhibition constants. CONCLUSION: The modeled structures give good explanations of the specificity of The law of play essential to inhibit the activity of eglin c mutants to furin / kexin. The results presented here provided quantitative structural and functional information concerning the role of the charge-charge interactions in the binding of furin / kexin and their inhibitors.