| Abstract: | Fast protein liquid chromatography on Superose 6 of crude extracts from the green alga Chlorella kessleri cultivated autotrophically in white light reveals several peaks with phosphofructokinase (PFK, EC 2.7.1.11) or pyruvate kinase (PK, EC 2.7.1.40) activity with molecular weights larger than the usually reported ones of 320–380 and 240 kDa, respectively. All other glycolytic enzymes are eluted as one peak each with a molecular weight corresponding to data from the literature. Indirect evidence indicates that the various forms of PFK and presumably PK are oligomers. The occurrence of different PFK species depends markedly on growth conditions such as wavelength of light: Red light leads to only one rather large PFK (1,580 kDa), blue light to two smaller species (760 and 360 kDa). All species are probably present in white light-grown cells (1,500, 1,050, 930, 700 and 440 kDa). The various light qualities do not significantly affect all other glycolytic enzymes. PK constantly exhibits four forms with molecular weights of 830, 680, 480, 305 kDa. Experiments with the chlorophyll-free mutant no. 20 of Chlorella kessleri support the assumption that oligomerization of enzymes is characteristic of regulatory enzymes, thereby providing the cell with an additional regulatory means. |
