Investigation on the binding site in heparin by spectrophotometry

Heparin has a variety of biological activities, most of them due to heparin 's high sulfate groups. To gain insight into the mechanism of activation of the spectroscopic probe with sulfate groups of heparin in vitro, we have u sed a cationic dye by a spectrophotometric method. It is considered that th e combination of heparin with methylene blue is due to noncovalent binding forces. Dye binding requires an organic chain structure form with sulfate g roups. The solution equilibria of the reaction system are discussed. A new linear regression equation has been proposed, in which the maximum binding number N expresses the binding ability of methylene blue (MB) with sulfate groups of heparin. The linear regression equation can estimate this paramet er. (C) 1999 Elsevier Science Ireland Ltd. All rights reserved.