title: Purification to homogeneity and amino acid sequence analysis of two anionic species of human interleukin 1.
abstract: Two anionic species of human IL-1 have been purified to homogeneity. These molecules were characterized as having pI of 5.4 and 5.2 and molecular weights identical to IL-1/6.8 (17,500). The specific activities of IL-1/5.4 and IL-1/5.2, as measured in the mouse thymocyte co-mitogenic assay, were identical to that of IL-1/6.8, namely 1.2 X 10(7) U/mg, with half-maximal stimulation observed at 2 X 10(-11) M. IL-1/5.4 and IL-1/5.2 were found to be antigenically distinct from IL-1/6.8 in an ELISA. IL-1/5.4 was structurally distinct from IL-1/6.8 based on reverse-phase HPLC or CNBr peptides. Intact IL-1/5.2 and three intact CNBr peptides of IL-1/5.4 were sequenced, with the identification of 74 amino acid residues. These sequences were found to correspond exactly with the amino acid sequence deduced from the IL-1-alpha cDNA reported by March et al.
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001666:Binding Sites, Antibody; D002851:Chromatography, High Pressure Liquid; D002852:Chromatography, Ion Exchange; D006801:Humans; D007375:Interleukin-1 / Q000145:classification / Q000276:immunology / Q000302:isolation & purification*; D007526:Isoelectric Point; D008213:Lymphocyte Activation; D008297:Male; D051379:Mice; D008809:Mice, Inbred C3H; D008970:Molecular Weight; D013601:T-Lymphocytes / Q000276:immunology
chemical_list: D007375:Interleukin-1