Clostridium oedematiens n-antigen, an enzyme decomposing tropomyosin.

Oakley, Warrack & Clarke (1947) demonstrated the existence in culture filtrates of various strains of Clostridium oedematiens of six antigens, designated as ac, P, y, 8, e and 4. The ac-antigen is produced by both type A and type B strains and is the main lethal agent in Cl. oedematien8 toxic filtrates. Its biochemical action is unknown, but one of its physiological effects is that of a capillary poison (A. A. Miles & E. M. Miles, 1952; A. A. Miles & J. M. Elder, unpublished), which may well be due to an attack on some constituent of the capillary wall. Since the chemistry of the capillary wall is unknown, it was decided to find out if the crude toxin had any action on some known proteins, particularly those which, by association in lipoprotein structures, might themselves conceivably be concerned in some permeability phenomenon, in the hope of getting some clue to the nature of the toxic action. It has been found that Cl. oedematiens type B (gigas) toxins contain an antigenic sulphydrylactivated enzyme decomposing tropomyosin. Serological tests show, however, that this enzyme is not identical with the lethal ac-toxin, nor with any of the other previously described antigens. It has therefore been designated specifically as Cl. oedematicn8 ij-antigen, and called a tropomyosinase. The characters of this enzyme are outlined below. Throughout this paper the word 'toxin' is used to denote the crude enzyme preparation, which was in fact toxic, and the specific antigens, distinguished in this toxin by serological tests, are denoted as a-antigen, a-antigen, etc.