title: Isolation of plasma membrane from protoplasts of Lolium multiflorum (ryegrass) endosperm cells.
abstract: Plasma membranes have been isolated from protoplasts of suspension-cultured ryegrass (Lolium multiflorum) endosperm cells. The protoplast membrane is coated before cell disruption with murine myeloma protein J539, a galactose-binding immunoglobulin A. The plasma membrane is labelled with 125I by using chemically or enzymically catalysed iodination techniques, or, more conveniently, by using 125I-labelled myeloma protein J539, which enables the membrane to be simultaneously coated and labelled. Protoplast lysis is effected by gentle mechanical means after swelling in hypo-osmotic medium. The plasma-membrane fraction is recovered at low centrifugal forces by fractionation of cell lysates on a discontinuous sucrose/sorbitol gradient. The plasma-membrane fraction is enriched 96-fold on a protein basis with respect to the specific radioactivity of 125I-labeled myeloma protein J539 in the homogenate. Electron microscopy showed long membrane profiles often associated with one another.
mesh_terms: D002352:Carrier Proteins / Q000494:pharmacology; D002449:Cell Aggregation / Q000187:drug effects; D002458:Cell Fractionation / Q000379:methods; D002462:Cell Membrane / Q000648:ultrastructure*; D002499:Centrifugation, Density Gradient; D008854:Microscopy, Electron; D008856:Microscopy, Fluorescence; D008857:Microscopy, Interference; D009194:Myeloma Proteins / Q000494:pharmacology; D009995:Osmosis; D006109:Poaceae / Q000648:ultrastructure; D011523:Protoplasts / Q000648:ultrastructure*; D012639:Seeds / Q000648:ultrastructure*
chemical_list: D002352:Carrier Proteins; D009194:Myeloma Proteins