ALPHA-2-8 SIALIC-ACID POLYMERS - SIZE, STRUCTURE, AND COMPOSITIONAL ANALYSIS

A series of three variable assay procedures is described to provide ov erlapping information on the size, structure, and composition of the a lpha 2-8 linked polysialic acid chains present on a wide variety of cr itical cell surface glycoproteins. Technical advances in instrumentati on have permitted the development of new applications for a methodolog y involving the sequential use of periodate and borohydride to modify terminal sialic acid residues. The procedures described here provide a rapid and facile assay for (a) the determination of polysialic acid c hain length, (b) the simultaneous identification of N-acetylneuraminic acid, N-glycolylneuraminic acid, and KDN (deaminated sialic acid) whe n present in a single preparation, (c) the ability to distinguish qual itatively between reducing and nonreducing polymers, and (d) the abili ty to determine the number of chains bound to a glycoprotein of known molecular weight. (C) 1994 Academic Press, Inc.