Question (76685) | Recombinant human Soluble TNF Receptor II protein (ab640)

Go to datasheet (ab640)

Question

Kindly clarify why is there difference in molecular weight (80 kDa and 19 kDa)
for human TNF receptor II full length proteins with catalogue numbers ab132049
and ab640, respectively.

Answer


Ab640 is a fragment of the TNF Receptor II protein. It is comprised of amino acids 33-205 but is an active protein. The activity was determined by its inhibitory effect of the TNF-α mediated cytotoxicity in murine L-929 cells. The ED50 for this effect in the presence of 0.25 ng/ml of Recombinant Human TNF-α, is 0.125 μg/mL. This 172 amino acid protein runs around 19 kDa in a SDS-PAGE gel.


Ab132049, on the other hand, is a recombinant protein comprised of amino acids 23-461 plus a GST tag (25 kDa). The 80 kDa band size is the result of the 438 amino acid protein plus the 25 kDa tag. This protein has not been shown to have activity. It is only validated for ELISA, WB, and SDS-PAGE.


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