Purification and characterization of human interleukin-1 alpha produced in Escherichia coli.
The production of human interleukin-1 alpha (IL-1 alpha) in Escherichia coli is described together with a method for its purification. The isolated protein was shown to be pure and physically homogeneous. The in vitro biological activity of IL-1 alpha was tested with the mononuclear-cell factor and the lymphocyte-activating factor assays. The specific activity determined with both assays was about 3 X 10(7) units mg-1 and is similar to that observed with recombinant human IL-1 beta. The purified protein was resolved by chromatofocusing into two species of isoelectric points 5.45 and 5.20 (75% and 25%, respectively, of the total protein). Both species had similar chemical properties and biological activities to the unfractionated protein. The charge difference between the species was attributed to the deamidation of a single Asn or Gln residue.
Wingfield
P
P
Payton
M
M
Graber
P
P
Rose
K
K
Dayer
J M
JM
Shaw
A R
AR
Schmeissner
U
U
D000596:Amino Acids / Q000032:analysis; D004247:DNA; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000378:metabolism*; D006801:Humans; D007375:Interleukin-1 / Q000096:biosynthesis / Q000302:isolation & purification* / Q000502:physiology; D007525:Isoelectric Focusing; D008970:Molecular Weight; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000502:physiology; D013056:Spectrophotometry, Ultraviolet; D014461:Ultracentrifugation
D000596:Amino Acids; D007375:Interleukin-1; D011994:Recombinant Proteins; D004247:DNA