ENZYMATIC-HPLC DETERMINATION OF THE AMOUNT AND DISTRIBUTION OF THE GALACTURONAN REGION IN PECTATE MOLECULES

Degradation percentages of pectates by exopolygalacturonate lyase, exo polygalacturonase (exo-PG), and exo-PG and endopolygalacturonase in co mbination can be accurately measured by our HPLC method. This enzymic- HPLC method was successfully used for the structural analysis of pecti c substances, which are usually composed of two distinct regions of li near galacturonan (GN) and branched rhamnogalacturonan (RG). The GN re gions were classified for convenience into four categories and the rel ative amounts of each GN region were represented by alpha approximatel y delta, viz., (alpha) GN chains having a nonreducing end, (beta) thos e having a reducing end, (gamma) those having both reducing and nonred ucing ends, and no neutral sugar residues, and (delta) those interpose d between two RG regions; in addition, (epsilon) the amount of the res idual galacturonate, mainly comprised in the RG regions. The procedure for the determination of alpha approximately epsilon was described in detail, and the results of application to several pectate preparation s were reported.