Analysis of α-amylase-derived pyridylamino-dextran sulfate oligomers by the combination of size-exclusion and reversed-phase high-performance liquid chromatography

In a previous study, we reported a novel method for the separation and quantification of a strong negatively charged material, dextran sulfate sodium (DSS), using fluorometric labeling with 2-aminopyridine and size-exclusion high-performance liquid chromatography. In the present study, we developed a method for the separation of pyridylamino-DSS (PA-DSS) using reversed-phase high-performance liquid chromatography (RPLC). In vitro enzymatic degradation of the PA-DSS was carried out using α-amylase. In RPLC, depolymerized PA-DSS was eluted on the basis of molecular mass (in the order pentamer, trimer, dimer, and monomer of PA-DSS) and separations were more sharply than in size-exclusion chromatography. The combination of RPLC and size-exclusion chromatography also separated depolymerized PA-DSS as effectively as RPLC alone.