Collect. Czech. Chem. Commun. 1983, 48, 3579-3588

Multi-chain action of exo-D-galacturonanase from carrot

Kveta Heinrichová and Jana Perečková

Institute of Chemistry, Slovak Academy of Sciences, 842 38 Bratislava


Two possible modes of action of exo-D-galacturonanase from carrot (E.C. were investigated; this enzyme catalyses the sequential hydrolytic cleavage of pectants and oligogalacturonans by a terminal action from the nonreducing end of the molecule. The experiments indicate that the investigated exo-D-galacturonanase degrades these substrates by a predominantly multi-chain mechanism. Distribution of degradation products of oligomeric substrates (hexa- and pentagalacturonide) under an optimal condition for the action of the enzyme (pH and temperature) indicates that a multi-chain enzyme attack with a prevalent simple collision is involved. Results of the enzyme degradation kinetics are in a good agreement with the above-mentioned presumption.