Inactivation of slow reacting substance of anaphylaxis (SRS-A) by lipoxidase.

Lipoxidase (E.C.1.13.1.13) inactivates rat SRS-A. The inactivation is time, temperature, and concentration-dependent. Linoleic acid and eicosatetraynoic acid inhibit the enzymatic deactivation of the mediator. It is concluded that SRS-A is a genuine substrate for lipoxidase and contains a cis, cis-1, 4-pentadiene structure. It is suggested that lipoxidase could play a major role in tissue removal of the mediator during hypersensitivity reactions.