| Autor: |
H V, Le, L, Ramanathan, J E, Labdon, C A, Mays-Ichinco, R, Syto, N, Arai, P, Hoy, Y, Takebe, T L, Nagabhushan, P P, Trotta |
| Rok vydání: |
1988 |
| Předmět: |
|
| Zdroj: |
The Journal of biological chemistry. 263(22) |
| ISSN: |
0021-9258 |
| Popis: |
We have purified recombinant human interleukin 4 (huIL-4), formerly named B-cell stimulatory factor-1, from supernatants of COS-7 monkey kidney and L-929 cells transfected with the cDNA for huIL-4. The purified protein exhibited a specific activity of 2.6 X 10(7) units/mg in a T-cell proliferation assay and consisted of multiple components on sodium dodecyl sulfate-polyacrylamide gel electrophoresis exhibiting Mr values of 15,000, 18,000, and 19,000. All forms of huIL-4 eluted on gel filtration chromatography with an apparent Mr of 22,000. Gas-phase microsequencing identified 26 and 8 amino acid residues at the N and C termini, respectively, all of which were consistent with the cDNA sequence. The site of processing of the signal sequence was found to occur between Gly-24 and His-25. Incubation with N-glycanase converted the 18- and 19-kDa variants to a 15-kDa form. Treatment with endo-beta-N-acetylglucosaminidase H reduced the molecular mass of the 18-kDa variant to 15 kDa, but did not have any apparent effects on the mass of the 19-kDa species. The removal of oligosaccharide by any of these treatments did not affect bioactivity in the T-cell proliferation assay. Neither O-glycanase nor endo-beta-N-acetylglucosaminidase D affected the molecular weight of any of these species. These data suggest that differences in carbohydrate structure account, at least in part, for the observed microheterogeneity. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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