Specific identification of collagens and their fragments by clostridial and anti-collagenase antibody.

A method specific for identification of collagens irrespective of type, species, or tissue origin, and of their derived fragments of molecular weight more than 10,000, is described. The method is based on the low-temperature affinity between clostridial collagenase and almost all types of collagens as well as on the affinity between collagenase and its antibodies. Various collagens or fragments derived from them by treatment with CNBr were separated by SDS-PAGE and immobilized onto a nitrocellulose membrane by a slot-blot technique or electrotransfer. Following binding of clostridial collagenase to a collagen or its fragments at 0 degrees C, the collagen-collagenase complex was fixed with glutaraldehyde. The complex was then allowed to bind anti-collagenase antibody at room temperature. The new complex was subsequently treated with 125I-labeled donkey anti-rabbit IgG and visualized as an autoradiogram. Under the conditions of low temperature used, the collagenase binds to collagens without causing their digestion. This procedure is specific for detection of soluble collagens as well as of insoluble collagens converted to fragments by treatment with CNBr. The method is uniquely suited for detection of fragments of tissue collagens. Also, it may serve as a prototype for methods for detection of other specific polymeric substances.