proteins. That is, changes in the carbohydrate content/ structure may result in a more or less sensitive dose response with each of the homogeneous lectin-based assays (i.e., change in the ED50 value for given glycoprotein). Such an approach is currently under study with the development of additional assays (e.g., sialic acid) and the specific application of this methodology for detecting changes in carbohydrate structure within recombinant glycoprotein therapeutic products.
ACKNOWLEDGMENTWe gratefully acknowledge I. J. Goldstein from the Biochemistry Department at the University of Michigan Medical School for his helpful preliminary discussions regarding this work. We also wish to thank Hanae Kaku from the same department for assisting us in determining the degree of saccharide substitution within the enzyme-saccharide conjugates used in these studies.