ANOMALOUS BEHAVIOR OF ACIDIC GRAPEVINE PEROXIDASE ISOENZYMES DURING PREPARATIVE ISOELECTRIC-FOCUSING

Preparative isoelectric focusing of grapevine peroxidases on glycerol- stabilized pH gradients in the Rotofor(TM) cell has been used to purif y peroxidase isoenzymes from the spent medium of suspension cultured c ells derived from mesocarp tissues of grape (Vitis vinifera cv. Monast rell) berries. The results showed that, under steady-state conditions, basic peroxidase isoenzymes focus well while acidic peroxidase isoenz ymes show anomalous behaviour during isoelectric focusing, leading to diffuse and/or multiband isoelectric focusing patterns. These results suggest that, although preparative isoelectric focusing in glycerol-st abilized pH gradients using the Rotofor cell may be a powerful tool fo r isoenzyme purification, the advantages of this technique may be seve rely hampered by the anomalous behaviour shown by acidic peroxidase is oenzymes during focusing.