THE RADIOPROTECTIVE POTENTIAL OF THE BOWMAN-BIRK PROTEASE INHIBITOR IS INDEPENDENT OF ITS SECONDARY STRUCTURE

The Bowman-Birk protease inhibitor (BBI), a serine-protease inhibitor, has been reported to exert both anticarcinogenic and radioprotective activity. In this work we examined whether this effect is mediated thr ough inhibition of serine-proteases of the trypsin-chymotrypsin type. Using Linearized forms of BBI, evidence will be provided that the seco ndary structure, obligatory for the protease inhibitory function, is n ot necessary for the radioprotective effect. Detailed analysis indicat ed that the radioprotective effect is correlated with the chymotrypsin -inhibitory region of the molecule. Using a synthetic nonapeptide lack ing protease inhibitor activity, the radioprotective effect of the tot al BBI molecule could be mimicked, indicating that the radioprotective effect is independent of the protease inhibitor function. (C) 1998 El sevier Science Ireland Ltd.