Title : Purification and characterization of natural human
interferon omega 1
Abstract :
- Two alternative cleavage sites for the signal peptidase
- Human interferon omega 1 ( IFN-omega 1 = IFN-alpha II1 ) is a recently discovered protein structurally related to IFN-alpha and -beta ; the biological activities of IFN-omega 1 and its physiological role are not known to date
- We have purified IFN-omega 1 from preparations of human leukocyte IFN , derived from peripheral blood leukocytes induced with Sendai virus, by two sequential cycles of monoclonal antibody affinity chromatography
- The resulting protein was at least 95% pure as determined by reverse-phase high performance liquid chromatography and showed an Mr of 24,500 upon sodium dodecyl sulfate-gel electrophoresis (theoretical Mr, 19,984)
- Amino acid sequence analysis revealed that only about 40% of the molecules have the NH2 terminus expected on the basis of the sequence similarity to IFN-alpha , whereas the others contain two additional amino acids
- This difference probably results from variable cleavage of the pre- protein by the signal peptidase
- No evidence for COOH-terminal heterogeneity was found
- Essentially all IFN-omega 1 molecules are glycosylated; enzymatic deglycosylation resulted in a reduction of the Mr to 20,500
- Experiments using several plant lectins indicated the presence of biantennary complex oligosaccharides containing neuraminic acid
- Two major peaks were observed upon chromatofocusing, with isoelectric points of 8.1 and 8.5
- The specific antiviral activity of purified IFN-omega 1 assayed on human cells was determined to be 2.7 x 10(8) IU/mg, similar to that of other human class I IFNs; potent antiviral activity was also observed on cells of bovine and ovine but not of equine or murine origin
Output (sent_index, trigger,
protein,
sugar,
site):
- 8. glycosylated, , -, Essentially all IFN-omega 1 molecules, -
Output(Part-Of) (sent_index,
protein,
site):
*Output_Site_Fusion* (sent_index,
protein,
sugar,
site):