DETECTION OF VANADATE-DEPENDENT BROMOPEROXIDASES IN PROTOPLASTS FROM THE BROWN-ALGAE LAMINARIA-DIGITATA AND L SACCHARINA

Protoplasts were prepared from the brown algae Laminaria digitata (Huds.) Lamour and L. saccharina (L.) Lamour in order to investigate vanadate-dependent bromoperoxidases. In both species bromoperoxidases were present in protoplasts and quantitative differences in electrophoretic bromoperoxidase patterns were observed between small surface-cell protoplasts and vacuolated cortical-cell protoplasts as well as between stipe and thallus preparations. Bromoperoxidase patterns obtained from protoplasts and cellwall fractions differed only in the absence of electrophoretically fast migrating isoforms in protoplasts. Since extracts from entire tissues also contained these isoforms the results suggest posttranslational modification of some bromoperoxidases during or after secretion into the cell wall. Biosynthesis of the major bromoperoxidase isoform was detected in protoplasts from L. saccharina incubated with 35S-methionine. © 1991, Gustav Fischer Verlag, Stuttgart. All rights reserved.