Sulfation as a collagen-specific reaction. The ultrastructure of sulfate collagen, basement membranes and reticulin fibers as shown by topo-optical staining reactions.

Abstract

Sulfation induces hyperbasophilia in connective tissue structures (fibrillary collagen, basement membranes and reticulin fibers), which appear metachromatic with toluidine blue at pH 1.0 and strongly birefringent with inversion of their positive birefringence into negative birefringence indicating transversally oriented and closely packed dye molecules on the micellar surface of collagen. Quantitative studies of the sulfation induced topooptical staining reaction following blocking of the vicinal glycol groups by periodate and the enzymatic removal of AMP support the view that carbohydrate glycol groups play only a minor part and the OH side-groups of the collagen peptide chains play the major part in the sulfation reaction of fibrillary collagen and basement membranes. After blocking of the vicinal glycol groups of carbohydrate components by periodate, sulfation induced toluidine blue hyperbasophilia with strong negative birefringence associated with selective proteolytic sensitivity are collagen-specific characeteristics due to sulfate esterification on the OH groups of the peptide chains of collagen, which provide new approach to the study of the ultrastructure of connective tissue elements in physiology and pathology.