Acid phosphatase in plant tissues I. Changes in activity and multiple forms in tea leaves and tomato fruit during maturation and senescence

Multiple forms of acid phosphatase varied in tea leaves (Camelliasinensis L.) depending on variety and the age of the leaves.Polyacrylamide gel electrophoresis indicated the presence ofsix multiple forms in extracts of young leaves and seven inextracts of mature leaves of the variety Hatzumomizi. VarietyBenihomare showed five bands in zymograms of young-leaf extractsand six in zymograms of mature-leaf extracts. In addition tothe appearance of the new band, the relative intensity of stainingin two other bands changed during maturation. One decreasedand one increased in intensity. The components were partiallyseparated by CM-cellulose chromatography and isoelectric focusing.Total activity of acid phosphatase did not change greatly ona fresh-weight basis during maturation and aging. Extracts of immature green tomato (Lycopersicon esculentum Mill.)fruit showed six bands on polyacrylamide gels. Isoelectric focusingand subsequent electrophoresis of the fractions obtained atdifferent pH values, produced evidence for seven acid phosphatasecomponents in tomato extracts. Unlike the situation with certainother climacteric fruit, acid phosphatase in tomato extractsdecreased steadily during ripening to a level of activity only25–40% that of immature green fruit extracts. It is thereforeconcluded that the onset of senescence in climacteric fruitsis not dependent on an increase in acid phosphatase. Substratespecificity, response to inhibitors, Km, and pH optima of partiallypurified fractions were similar to those of tea-leaf extracts. (Received November 29, 1972; )