Figure 2.

PG2 hydrolysis of cell walls from mature-green cv Ailsa Craig tomato fruit. Cell walls (5 mg) preloaded with purified PG2 (0.44 μg protein mg⁻¹ of cell wall) were incubated in 4 mL of 20 mm NaOAc and 150 mm NaCl or 20 mm KOAc and 100 mm KCl for 2 h at 34°C. Reaction mixtures were filtered and soluble uronic acids measured as described in Methods. Activity is expressed as micrograms of galacturonic acid equivalents released per milligram of cell wall. •, 150 mm NaCl; ○, 100 mm KCl.