“…Interaction studies performed in vitro at different pH values (pH 5.5, 7.5 & 8.5; pH 7.5; pH 5.5 & 7.5; pH 6.5, 7.5 & 8.5) indicated formation of a stoichiometric 1:1 complex of PMEIs with endogenous PMEs but also with enzymes from other species [ 41 , 53 , 56 , 57 ]. For example, Jolie et al [ 58 ] showed that purified PMEI from kiwi can bind to PMEs from carrot and broccoli (at pH 6.5), whereas tomato and Arabidopsis PMEIs can interact and inhibit PMEs from orange (at pH 7.5 and pH 7, respectively) [ 30 , 59 ]. On the other hand, plant PMEIs do not seem capable of inhibiting fungal or bacterial PMEs, as was shown for PMEI1 and PMEI2 from Arabidopsis, which did not affect PME activity of Botrytis cinerea [ 26 ].…”