Immunochemical identification of an actin-like protein from soybean seedlings

Abstract

Microfilaments are recognised as ubiquitous cytoskeletal and contractile elements found in virtually all types of cells. Indeed, the major protein component of these fibrillar structures, actin, has been isolated from a variety of cells1–5. A number of laboratories have recently reported ultrastructural observations of microfilaments in plant cells such as Avena sativa, Nicotiana tabacum, Nitella flexilis, Amaryllis belladonna, Haemanthus katherina, Mougeotia, Mimosa and Chara6–13. Preliminary studies on the identification of the actin subunit of these structures have also been reported for Nitella, Phaseolus vulgaris and Lycopesicon esculentum14–16. More detailed studies have been made on actin isolated from the cellular slime mould, Dictyostelium discoideum17,18. We report here the isolation, from extracts of soybean (Glycine max) seedlings, of a protein that binds rabbit antibodies directed against calf thymus actin. The results suggest the presence of an actin-like polypeptide chain in soybean cells.