Coagulins

Coagulins, a term with various meanings. In the chemistry of blood coagulation, it is equivalent to fibrin-ferment, plasmin, and thrombin. Loeb introduced it to designate fibrin-forming substances released under pathological conditions (tissue coagulins). These coagulins are present in tissue extracts; they are abundant in the lungs, muscles, liver, and kidneys, as well as in the walls of blood vessels. They are to some degree specific, as they act predominantly or exclusively on homologous fibrinogen. Coagulins probably consist of a compound of a protein with anticoagulating properties and cephalin. During autolysis, coagulins are destroyed. Coagulins are also found among bacterial products. According to Loeb's research, the staphylococcus aureus is the most powerful producer of coagulation. Tuberculous, diphtheria, typhoid, xerosis bacteria, and streptococci do not have coagulating action, while Bacillus pyocyaneus, prodigiosus, and coli occupy an intermediate position. Since coagulins are present in tissue cells, it is possible that, acting on cellular proteins, they also cause coagulation necrosis. Additionally, the term coagulins is used as a synonym for precipitins. Nicolle calls coagulins good antibodies, as they prevent the action of albuminolysin on the antigen and the release of toxic breakdown products. The action of bacterial toxins was also associated with coagulation. Toxins have much in common with enzymes: activity in high dilutions, adsorption from solutions by indifferent precipitates, and easy destructibility. This led to the idea of classifying toxins as enzymes. Enzymes, however, are characterized by a specific chemical action on a substrate. A number of facts were presented in support of the opinion that toxins belong to coagulating enzymes (toxico-coagulins). This opinion is confirmed by the fact that substances harmful to bacteria, produced by animals, i.e., antibodies, also act by means of coagulation (agglutination, precipitation, flocculation).