help about GST-fusion protein SDS-PAGE

Jen jrobertson1 at
Thu Aug 29 19:27:48 EST 2002

are you saying that you cleaved your target protein from the GST and
this target protein runs higher than native?

there is always case where the recombinant protein has different
glycosylation and phosphorylation levels than in vivo - and these two
would both have an effect on mobility in a gell - but i don't know
about a few KDa's worth.....

On 29 Aug 2002 11:34:27 -0000, fly1234 at wrote:

>I expressed a GST-fusion protein in BL21 and purifid it with glutathione beads. After SDS-PAGE, I was surprised to find that the apparent Molecular weight of the purified product (in 20mm glutatione buffer) was several KD larger than that of pre-purified target protein (showed as a bold band) in cell lysate. Does anybody have the same experience? Could you help me?

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