The enzyme has been isolated from the bacterium Listeria innocua. It catalyses the reversible phosphorolysis of ¦Â-(1¡ú2)-D-glucans. The minimum length of the substrate for the phosphorolytic reaction is 3 D-glucose units. In the synthetic reaction starting from sophorose and ¦Á-D-glucose 1-phosphate the average polymerisation degree is 39.