Pectinolytic enzyme that has a positive effect in the apple hot-mash liquefaction process. This endolyase hydrolyzes the alpha-L-rhamnopyranosyl-(1,4)-alpha-D-galacturonopyranosyl glycosidic linkage by beta-elimination, thereby generating oligosaccharides terminating at the non-reducing end with a hex-4-enopyranosyluronic acid residue. Endotype eliminative cleavage of L-alpha-rhamnopyranosyl-(1->4)-alpha-D-galactopyranosyluronic acid bonds of rhamnogalacturonan I domains in ramified hairy regions of pectin leaving L-rhamnopyranose at the reducing end and 4-deoxy-4,5-unsaturated D-galactopyranosyluronic acid at the non-reducing end. Optimum pH is 6.0, enzymatic activity becomes unstable below this value. Optimum temperature is 50 degrees Celsius. Belongs to the polysaccharide lyase 4 family.