Catalyzes the depolymerization of both polygalacturonate and pectins of methyl esterification degree from 22 to 89%, with an endo mode of action. In contrast to the majority of pectate lyases, displays high activity on highly methylated pectins. Is not able to cleave trigalacturonate. Does not degrade xylans and carboxymethylcellulose (CMC). Eliminative cleavage of (1->4)-alpha-D-galacturonan to give oligosaccharides with 4-deoxy-alpha-D-galact-4-enuronosyl groups at their non-reducing ends. Eliminative cleavage of (1->4)-alpha-D-galacturonan methyl ester to give oligosaccharides with 4-deoxy-6-O-methyl-alpha-D-galact-4-enuronosyl groups at their non-reducing ends. Binds 1 Ca(2+) ion per subunit. Strongly inhibited by Ba(2+). To a lesser extent, is also inhibited by Sn(2+), Mg(2+) and Ag(+). Inhibited by EDTA in vitro. Optimum pH is 10. Is stable for 1 hour at 40 degrees Celsius in the pH range 4.0-8.0. Optimum temperature is 50-55 degrees Celsius. More than 50% of maximum activity is found in the temperature range 40-60 degrees Celsius. Retains more than 50% of the initial activity after 4 hours incubation at 40 degrees Celsius at pH 10, while at 50 degrees Celsius only 1% of the initial activity is found after the same treatment. Glycan metabolism; pectin degradation; 2-dehydro-3-deoxy-D-gluconate from pectin: step 2/5. Belongs to the polysaccharide lyase 3 family.