Distribution of Isocitrate Lyase in Induced and De-adapting Cells of the Green Alga Chlorella fusca

SUMMARY: Colloidal gold labelled goat anti-rabbit IgG has been used in conjunction with a rabbit anti-isocitrate lyase antibody, to locate isocitrate lyase in the green alga Chlorella fusca. Under induced conditions isocitrate lyase was apparently uniformly distributed in the cytoplasm. Under de-adapting conditions (when enzyme activity had diminished by 45% from the fully induced level), the amount of gold label bound to sections was proportionately reduced although its cytoplasmic location was unchanged. Immunodetection of protein transferred to nitrocellulose after electrophoresis confirmed that there was loss of isocitrate lyase protein during de-adaptation.