title: Characterization of C1q-binding material released from the membranes of Raji and U937 cells by limited proteolysis with trypsin.
abstract: C1q-binding material was released, by limited proteolysis with trypsin, from the membranes of intact cells of the Raji lymphoblastoid cell line and the U937 monocytic cell line. The trypsin-digested C1q-binding material was purified from the supernatant of the trypsin-treated cells by affinity chromatography on C1q-Sepharose followed by gel filtration. On gel filtration in non-dissociating conditions this material behaved as a molecule of approx. Mr 65,000, while on SDS/polyacrylamide-gel electrophoresis two peptides of Mr 10,000 and Mr 15,000 were seen under both reducing and non-reducing conditions. Evidence for the synthesis of the C1q-binding material by both Raji and U937 cells was obtained by biosynthetic-labelling studies using [35S]cysteine and [35S]methionine.
authors.affiliation: Department of Biochemistry, University of Oxford, U.K.
authors.forename: A
authors.initials: A
authors.lastname: Erdei
authors.forename: K B
authors.initials: KB
authors.lastname: Reid
mesh_terms: D000818:Animals; D002460:Cell Line; D002846:Chromatography, Affinity; D002850:Chromatography, Gel; D003166:Complement Activating Enzymes / Q000378:metabolism*; D003172:Complement C1 / Q000378:metabolism*; D015922:Complement C1q; D003545:Cysteine / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D008562:Membrane Glycoproteins; D008565:Membrane Proteins / Q000378:metabolism*; D008715:Methionine / Q000378:metabolism; D010434:Pepsin A; D011951:Receptors, Complement / Q000302:isolation & purification / Q000378:metabolism*; D013462:Sulfur Radioisotopes; D014357:Trypsin / Q000494:pharmacology*
chemical_list: D003172:Complement C1; D008562:Membrane Glycoproteins; D008565:Membrane Proteins; D011951:Receptors, Complement; D013462:Sulfur Radioisotopes; C032402:complement 1q receptor; D015922:Complement C1q; D008715:Methionine; D003166:Complement Activating Enzymes; D014357:Trypsin; D010434:Pepsin A; D003545:Cysteine