title: Glucosamine-labelled envelope proteins of Escherichia coli K-12. II. Location in inner and outer membranes.
abstract: Outer and inner membranes were prepared from a culture of a glucosamine- and leucine-requiring mutant of Escherichia coli K-12, which was grown on L-[4,5-(3)H2]leucine and D-[1-(14)C]glucosamine and "chased" with unlabelled medium. Phenol-soluble glycoproteins were obtained from these membranes after phospholipid extraction. Sodium dodecyl sulfate-disc electrophoresis of the outer-membrane glycoproteins separated two components which were labelled with both isotopes and had a fast (F) and intermediate (I) migration. Dodecyl sulfate electrophoresis of the inner-membrane glycoproteins showed that only the F band incorporated both 14C and 3H labels. The 3H to 14C ratio in the F band from the outer membrane was completely different from the isotopic ratio in the F band from the inner membrane, indicating that these components were not identical despite their similar molecular weights. The F bands from both membranes lost their label during the chase with unlabelled medium, while the I band remained relatively stable. Chloroform-soluble 14C label extracted from the outer membrane decreased during the chase. In contrast, the chloroform-soluble 14C from the inner membrane, accumulated during the chase.
mesh_terms: D001426:Bacterial Proteins / Q000032:analysis*; D002458:Cell Fractionation; D002462:Cell Membrane / Q000032:analysis*; D002499:Centrifugation, Density Gradient; D002725:Chloroform; D004589:Electrophoresis, Disc; D004926:Escherichia coli / Q000032:analysis*; D005944:Glucosamine / Q000032:analysis*; D006023:Glycoproteins / Q000032:analysis*; D007930:Leucine / Q000032:analysis; D010636:Phenols; D012995:Solubility
chemical_list: D001426:Bacterial Proteins; D006023:Glycoproteins; D010636:Phenols; D002725:Chloroform; D007930:Leucine; D005944:Glucosamine