Purification and characterization of a high-molecular-weight form of recombinant human interleukin-2.
During purification of recombinant Interleukin-2 (rIL-2) by reversed-phase HPLC, early fractions are discarded due to the presence of an unidentified form of rIL-2. A procedure has been developed to isolate and purify this unidentified form of rIL-2. The purification process involves two chromatography steps and utilizes a Bakerbond Carboxy-Sulfon (CS) column under two different conditions. This material, designated as a high-molecular-weight form of rIL-2 (HMWrIL-2), exhibits lower mobility during SDS-PAGE and has a pI which is approximately one unit less than that of rIL-2, but has similar bioactivity to rIL-2. Structural analysis through enzymatic cleavage, HPLC peptide mapping, mass spectrometry, sequencing, and amino acid composition revealed that the difference between these two proteins is a C-terminal extension of 11 amino acids. This extension could be the result of a nonstandard translation event.
Ahmad
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Z
Bioprocess Department, Hoffmann-La Roche, Nutley, New Jersey 07110.
Ciolek
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D
Pan
Y C
YC
Michel
H
H
Khan
F R
FR
D000595:Amino Acid Sequence; D007376:Interleukin-2 / Q000737:chemistry / Q000302:isolation & purification*; D008969:Molecular Sequence Data; D008970:Molecular Weight; D011994:Recombinant Proteins / Q000302:isolation & purification
D007376:Interleukin-2; D011994:Recombinant Proteins