Isozymes in nutrient medium of suspension-cultured apple cells (Malus sylvestris Mill.)

Abstract

The time course of the activities of esterase, ct-galactosidase, and fl-glucosidase in cell sap and nutrient medium in in vitro cultured apple cells (Malus sylvestris Mill.) was studied.The corresponding isozyme patterns and the intracellular and extracellular isozyme patterns of acid phosphatase and polyphenol oxidase were compared using isozyme visualization methods adapted to ultra-thin-layer isoelectric focusing. Neither quantitative (total activity) nor qualitative (isozyme pattern) data were congruent for cell saps and nutrient media. Malate dehydrogenase, malic enzyme, and glutamate dehydrogenase occurred in cell sap only. The extracellular activities probably originate to a great part from a programmed release by intact cells. Nutrient media of plant cell cultures constitute a rich source of active plant isozymes.