title: Plant microbody proteins, III. Labelling of the peroxisomal membrane protein SP-63 in vitro and in vivo.
abstract: Methods were developed to charcterize membranes and membrane components of leaf peroxisomes from Lens culinaris. While microbodies from etiolated young leaves exhibited an equilibrium density of 1.19 g/cm3, older leaves or leaves exposed to light for increasing periods of time contained microbodies banding at higher densities up to 1.235 g/cm3. Similar values were also found for the corresponding microbody membranes, which could be labelled with diazotized [35S]sulphanilic acid. Labelling was also performed using proteins extracted from the membranes. Their main structural protein (SP-63) was solubilized with sodium dodecylsulphate and labelled with fluorescent compounds as well as with diazotized [35S]sulphanilic acid or [3H]iodoacetic acid. These conversions greatly facilitate all analytical procedures, e.g. tracing the migration of SP-63 in gels or the movement in sucrose gradients containing sodium dodecylsulphate during zonal centrifugation. Also, labelling of SP-63 in vivo was accomplished when labelled amino acids were infused into etiolated leaves while exposing them to light.
mesh_terms: D003624:Darkness; D007553:Isotope Labeling; D008027:Light; D008566:Membranes / Q000032:analysis; D008722:Methods; D008830:Microbodies / Q000032:analysis*; D009940:Organoids / Q000032:analysis*; D010940:Plant Proteins / Q000032:analysis*
chemical_list: D010940:Plant Proteins