Peptide composition and enzyme activities of isolated pyrenoids from the green alga Bryopsis maxima
Pyrenoids of Bryopsis maxima contained several minor components other than the large subunit (LS) and the small subunit of ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco). Among the minor components, polypeptides of 95, 67, and 41 kDa reacted with an antibody against the LS polypeptide. Amino acid sequences of these polypeptides were determined and compared with that deduced from the LS gene (rbcL) screened from the chloroplast DNA library of B. maxima. The N-terminal sequence of the LS peptide was not post-translationally processed and was almost identical with those of the polypeptides of 91, 67, and 41 kDa. The starch grains surrounding the pyrenoids contained a polypeptide of 66 kDa that was assigned as starch synthase. Key words: Bryopsis maxima, nitrate reductase, pyrenoid, rbcL, Rubisco, starch synthase.