Analysis of the Components Released from Potato Tuber Tissues during Maceration by Pectolytic Enzymes

Endo-pectin lyase and endo-polygalacturonase of Aspergillus japonicus attack the middle lamella of plant tissue and cause tissue maceration. Galacturonides, neutral sugars, and proteins were released from potato tuber tissues during maceration by both purified enzymes. These three components accounted for 92% of the soluble products. The neutral sugars released were rhamnose, arabinose, and galactose with a molar ratio of 1:3:15. They were covalently linked to galacturonides. Over 85% of the galacturonides released by the enzymes were short chain products, which indicated that a large portion of the main chain of pectic substances is a homogalacturonan. The results of chromatography on columns of Sephadex G-100 and DEAE-cellulose suggested that a protein component may be attached to pectic substances. This protein did not contain hydroxyproline and, therefore, was different from the cell wall structural glycoprotein.