Suramin--a potent reversible and competitive inhibitor of complement systems.

  • 1 January 1972
    • journal article
    • Vol. 10  (1) , 127-38
Abstract
Since the interaction of complement components is in essence a chain reaction of proenzyme activation to enzymes, suramin, a potent inhibitor of at least six different enzymes, is shown to be an efficient inhibitor of the complement system. The inhibition is rapid, reversible and nonspecific; the interactions of SHEA and C1, SHEAC1 and C4, SHEAC14 and C2, SHEAC142 and C3–9 are inhibited by microgram quantities of the inhibitor. By applying standard enzyme-substrate-inhibition assay methods, suramin is shown to inhibit SHEAC1 and C4 as well as SHEAC14 and C2 interactions competitively. This mode of inhibition is in contrast with that of most of the known inhibitors which are anticomplementary by virtue of destroying or activating the complement components so that they are no longer available for further interactions. When suramin is mixed with serum its rate of dialysis is greatly reduced; such a behaviour may be explained by the high affinity of suramin for protein molecules to form complexes. Although haemolytic complements of different species origins have variable susceptibility to suramin inhibition, it is one of the most potent complement inhibitors as yet available for experimental use.