Precipitation during dialysis - (Jun/22/2012 )

Hi everyone,

Recently, I did some dialysis for coupling reaction. The IgG (protein used for coupling dye) is in PBS buffer contain 30% glycerol. When I added NHS-SS-biotin in IgG solution and finished coupling reaction. I did dialysis against PBS to remove exceed biotin reagent. But I found precipitation in the dialysis tube (from spectrum lab). All process was done at 4C.

My hypothesis is glycerol crystalization??? I am not sure if it is my IgG protein..

Anyone have any idea???

I will run western blot tomorrow...

Thanks!!!

Best,

Hiroshi

I think I now .... the antibody I bought is not 100% pure. Maybe it's other protein in the solution precipitated during the dialysis

unlikely glycerol precipitated; maybe the antibody: solubility was decreased because of cooling AND loss of glycerol