[Molecular interaction between synthetic spirobutenolides and C1 esterase normal inhibitor]

Previously we have found that spirobutenolide synthetic derivatives show an inhibiting effect on C1 esterase activity. In contrast to these compounds some derivatives in the same series reveal an esterase activity when they are added to a C1 esterase preparation in presence of normal serum. The present work shows that this effect reflect an interaction with natural inhibitor C1 INH.