The interaction of tumor localizing porphyrins with collagen and elastin

The interaction of a series of tumor localizing porphyrins with collagen and elastin was determined. All the porphyrins studied bound to both acid soluble and insoluble collagen, but to differing extents, as well as to elastin. The extent of binding to acid soluble collagen was greater than that to insoluble collagen. The major consequence of this association was a marked decrease in the solubility of the acid soluble collagen suggesting stabilization of the fibrillar structure of the collagen had occurred. Evidence was also obtained indicating the porphyrins could bind to collagen alpha-chains. The relevance of these findings to porphyrin localization is discussed.