endotoxin detection

[Guest Kitty]

Hi , I work with a phosphorylcholine containing, tetrameric, N-linked glycoprotein (>200kDa) which is produced in, as close as possible, an endotoxin free environment however when we routinely test it using either a gel clot assay or a chromogenic microplate assay we get very inconsistent results eg adding polymixin to our sample has only a minor effect as does adding glucan blocker. Serial dilution of our sample only has a limited effect. We are presuming that this may have something to do with the structure of our molecule but are at a loss as to what this could be. Has anyone else experienced problems like these or even better has an explanation!

 

Thanks

 

Kitty