Membrane protein concentration - (Feb/07/2013 )

I'm preparing membranes from CHO cells cultured in Corning 75cm² flasks. My protocol for this is generic: Scrape cells at 90~100 confluence, homogenise and spin at 60,000g. My final pellet is resuspended in 3ml of buffer.

But when I got to my Bradford assay to determine protein concentration, I'm finding that from one flask, I get around 0.5mg/ml. Although I resuspend my pellet in 3ml, which might be high, I'm not entirely convinced that this is all I get out of it?

I was wondering if anyone has experience in this, and may have an idea of how much protein one may expect to get?

Thank you for your time.

This doesn't look like a good protocol to me. usually fractionation protocols have more centrifugation steps. we have many protocols at the main protocol-online.org page. That's where I found my own protocol.