Cell Wall-bound Enzyme

Abstract

Tomato cell wall fraction washed three times with water was used as a preparation of insoluble β-fructofuranosidase (β-FFase). The insoluble β-FFase could not be released from cell wall fraction in the presence of substrate. Comparative studies on kinetics of soluble and insoluble forms of β-FFase were performed. There were no marked differences between the two forms with regard to pH dependency, Michaelis constant and some inhibitors. Considerable difference was observed between the two forms in both temperature sensitivity and dependency. The soluble form was no longer active at 55°C, but the insolubleform still retained 65%, of the maximum activity at this temperature. There was a marked break in the Arrhenius plot at 19°C with the insoluble form, but a linear line was obtained at a temperature range of 10°C to 30°C with the soluble form. Activation energies were 10, 800 and 17, 300 cal/mole in the lower temperature range (below 19°C) for the insoluble and the soluble form, respectively. But they differed widely at higher temperatures (above 19°C); i.e., 53, 600 and 17, 300 cal/mole, respectively.