Characterization of the interaction between methylene blue and glycosaminoglycans

The methylene blue (MB) method for glycosaminoglycans (GAGs) assay is commonly used because of its sensitivity and convenience. The basis of the assay method is the binding of dye to GAGs, with production of a dye-GAGs complex which absorbs decrease at 664 nm, but the mechanism of the binding process is not well understood. The research attempts to gain better understanding of the assay system through spectrophotometric binding studies carried out on selected GAGs under normal GAGs assay. In this paper, two mathematical models for the binding process are proposed. These models are tested for their ability to estimate the number of dye-binding sites (n, N) and condition binding constant (K) from GAGs assay data. (C) 1999 Elsevier Science B.V. All rights reserved.