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 also able to cleave trigalacturonate to galacturonic acid and unsaturated digalacturonate. 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. Optimum pH is 10. Optimum temperature is 65 degrees Celsius. Thermostable at 50 degrees Celsius in buffers at pH 7. Glycan metabolism; pectin degradation; 2-dehydro-3-deoxy-D-gluconate from pectin: step 2/5. Hg(2+) could replace calcium ion. Belongs to the polysaccharide lyase 3 family.