POLYGALACTURONASE ISOZYMES IN THE CYANOLICHEN PELTIGERA-CANINA

Polygalacturonase is produced by the cyanolichen Peltigera canina. In cell free extracts of thalli, enzyme activity was detected in the solu ble fraction and in the cell wall. Polygalacturonase was also secreted to the incubation medium. Three forms of the enzyme differing in isoe lectric point were detected. One form, with pi around 6.0, appeared in soluble and cell wall fractions and also was secreted to the incubati on medium. Two other forms were detected, one in the soluble fraction, whose pi is around 5.0, and the other in the cell wall fraction, with pI 7,0. These results are discussed considering the different cell wa ll composition of the symbionts and the fact that Peltigera canina is tightly joined to the tissues of mosses, on which it grows.