title: Purification and characterization of a humoral opsonin from the solitary urochordate Styela clava.
abstract: 1. We have previously identified opsonic activity in the plasma of the solitary urochordate, Styela clava. 2. Here, we report the purification and further characterization of the opsonic molecule. 3. Two purification methods were employed. 4. Gel filtration yielded one strongly opsonic fraction that contained a single, electrophoretically-resolved protein. 5. Opsonic activity was dose-dependent and sensitive to tryptic digestion and heat denaturation. 6. SDS-PAGE and calibrated gel filtration indicated the opsonic protein was a 17.5 kDa monomer while isoelectrofocusing indicated a single pI of 7.0. 7. In an alternative procedure, a similar opsonic activity and protein were isolated by affinity purification using whole yeast cells.
authors.affiliation: Department of Anatomy and Cell Biology, School of Medicine, University of California, Los Angeles 90024.
authors.forename: K L
authors.initials: KL
authors.lastname: Kelly
authors.forename: E L
authors.initials: EL
authors.lastname: Cooper
authors.forename: D A
authors.initials: DA
authors.lastname: Raftos
mesh_terms: D000818:Animals; D002850:Chromatography, Gel; D004591:Electrophoresis, Polyacrylamide Gel; D006434:Hemocytes / Q000276:immunology; D007526:Isoelectric Point; D008970:Molecular Weight; D009895:Opsonin Proteins / Q000737:chemistry / Q000302:isolation & purification*; D014561:Urochordata / Q000737:chemistry / Q000276:immunology*
chemical_list: D009895:Opsonin Proteins