title: An immunological approach to enrich a mitotic stimulator and to reveal G2-phase-specific proteins in Physarum polycephalum.
abstract: Purified antibodies from an antiserum against S-phase proteins of the myxomycete Physarum polycephalum were attached to protein-A-Sepharose CL-4B. A late G2-phase extract that contained a mitosis-stimulating protein was applied to this immunoadsorbent, and the mitosis-stimulating protein was enriched by a factor of ten. This protein, which is present in the cell in low amounts, is synthesized in late G2 phase and obviously degraded in a later stage of the cycle. Immunoadsorption of a G2-phase extract with anti-S-antibodies decreased the 700 main proteins to 20 as demonstrated by two-dimensional gel electrophoresis. No difference in protein pattern could be observed on two-dimensional gels between S-phase and G2-phase extracts before and after immunoadsorption with anti-S-antibodies. This indicates that there are no G2-phase-specific proteins among the 700 most abundant proteins of Physarum polycephalum.
mesh_terms: D004591:Electrophoresis, Polyacrylamide Gel; D007163:Immunosorbent Techniques; D007399:Interphase; D008934:Mitogens; D008938:Mitosis; D010804:Physarum / Q000378:metabolism*; D011506:Proteins / Q000378:metabolism*
chemical_list: D008934:Mitogens; D011506:Proteins