Isolation and partial characterization of pyrenoids from the brown alga Pilayella littoralis (L.) Kjellm

In order to isolate high yields of pyrenoids from the brown alga Pilayella littoralis it is necessary to pretreat them with 0.1% HgCl2 in sea water for 3 h. Without this pretreatment there is a substantial loss of pyrenoid ground substance and yields are low. Pyrenoid fractions of high purity have been obtained using silica sol gradients. A partial characterization has shown the pyrenoid to be proteinaceous and lacking chlorophyll. SDS polyacrylamide gel electrophoresis has shown that the majority of protein present is accounted for by two polypeptides which resemble the large and small subunits of ribulose-1,5-bisphosphate carboxylase (EC 4.1.1.39).