<p>(<b>A</b>) Intercellular washing fluid (IWF) was extracted from six-week-old Arabidopsis plants using an infiltration-centrifugation method. About 30 fully-expanded rosette leaves were detached from 10 plants, IWF from transgenic and control plants were produced, with their proteolytic activities determined by degradation of myelin basic protein (MBP) and fractionation on 20% SDS-PAGE. (<b>B</b>) Activity of the IWF from At2-MMPox plants was inhibited by EDTA. (<b>C</b>) Degradation of MBP by recombinantly produced Mat-MMP2 (predicted mature At2-MMP). The Mat-MMP2 protein starts from the amino acid D in the cysteine switch motif PRCGNPD and ends before the C-terminal transmembrane domain. Both Mat-MMP2 and proteins produced from empty vector (EV) transformed cells were harvested from the supernatant after three times sonication. MBP was incubated with or without the presence of Mat-MMP2 at 37<sup>°</sup>C for 0 min and 30 min. Samples were separated by 20% SDS-PAGE.</p
