Inflammatory proteins: chemical and biological aspects.

Mediators of the inflammatory system can be broadly described as those that pre-exist and are released by active secretory mechanisms from storage granules (as in the case of vasoactive amines within cytoplasmic granules of mast cell), those that are biosynthetically generated de novo (as in the case of prostaglandins) and those that are produced by enzymatic cleavage of a precursor protein. With regard to the last category, cleavage of the precursor protein releasing a biologically active fragment occurs following activation of a plasma proenzyme or the release of a stored protease from within a cell.