Catalyzes the depolymerization of both polygalacturonate and pectins with low (20-34%) and high (90%) levels of methyl esterification, with an endo mode of action. In contrast to the majority of pectate lyases, displays high activity on highly methylated pectins. Does not show xylanase and cellulase activity. 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. Optimum pH is 10.5. Optimum temperature is 45 degrees Celsius. Glycan metabolism; pectin degradation. Belongs to the polysaccharide lyase 3 family.