Enzymic-HPLC Determination of the Amount and Distribution of the Galacturonan Region in Pectate Molecules

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Abstract
Degradation percentages of pectates by exopolygalacturonate lyase, exopolygalacturonase (exo-PG), and exo-PG and endopolygalactur-onase in combination can be accurately measured by our HPLC method. This enzymic-HPLC method was successfully used for the structural analysis of pectic substances, which are usually composed of two distinct regions of linear galacturonan (GN) and branched rhamnogalacturonan (RG). The GN regions were classified for convenience into four categories and the relative amounts of each GN region were represented by α∼δ, viz., (α) GN chains having a nonreducing end, (β) those having a reducing end, (γ) those having both reducing and nonreducing ends, and no neutral sugar residues, and (δ) those interposed between two RG regions; in addition, (∊) the amount of the residual galacturonate, mainly comprised in the RG regions. The procedure for the determination of α∼∊ was described in detail, and the results of application to several pectate preparations were reported