Cell Wall Metabolism in Ripening Fruit

Abstract

Mature ;Bartlett' pear (Pyrus communis) fruits were ripened at 20 C. Fruits at different stages of ripeness were homogenized, and extracts of the low speed pellet (crude cell wall) were prepared. These extracts contained polygalacturonase, pectin esterase, and activity against seven p-nitrophenyl glycoside substrates. Polygalacturonase, alpha-galactosidase, and alpha-mannosidase increased in activity as the fruit ripened. Cellulase and activities against pear wall xylan and arabinan were absent from the extracts.