1 reply to this topic

[yongyk]

Dear friend,

Again, this is regarding to my cloning work. I clone my protein in pQE-30 vector and tranfect into E.Coli (Qiagen product). After induced by IPTG, the bacteria was harvested and protein of interest was purified using Ni-NTA method acroding to manufacturer instruction.

However when I run SDS-PAGE, I still can see a lot of my protein in the cell lysate. My protein is a soluble protein, why it can be mixed with cell lysate??

From MERCK website I got this information that: "soluble protein has to be span at 10,000g at least 30 min before it can be seperated from insoluble protein/homogenized in supernatant."
Is that true?

I will be glad if someone can comman on this

Thank everybody : )

Yong

[leekaming]

I do not quite understand your problem. If a protein is expressed in E.coli, after sonication, the protein is normally in cell lysate.