A new mechanism for the terminal stages of complement hemolysis based on kinetic and thermodynamic rationales

Okada, Boyle and Borsos (1) made a study, reported in this journal, of the temperature dependence of and effects of preincubation on the terminal reactions in complement hemolysis. They suggested that EAC1–9 inserted could go on to lysis by either of two reaction paths and also that there is an enzyme catalyzed step. In this paper we show by kinetic and thermodynamic analysis a) that their results are inconsistent with such a double path mechanism and b) that their data are quantitatively compatible with a fairly conventional Michaelis-Menten mechanism. Although we agree with Okada et. al that their data are consistant with the participation of an enzyme in the terminal stages of complement hemolysis, the type of rate laws referred to in this paper could apply to some non-enzymatic reactions.