Binding of 1-anilinonaphthalene-8-sulfonic acid to type I collagen

The existence of a hydrophobic cluster on the COOH-telopeptides of type I collagen has been observed by studies on the binding of 1-anilinonaphthalene-8-sulfonic acid (ANS) to this protein. Collagen contains one binding site for the fluorescent probe. This hydrophobic cluster remains after pepsin digestion thus indicating that it is formed by the undegraded portions of the COOH-extrahelical ends of the protein. Energy transfer from tyrosine to ANS has been observed. The triple helix of collagen does not bind ANS.