Total Protein in COS-7 Cells - (Jan/09/2014 )

Hi all,

How much total protein should I be expecting from COS-7 cells? 

I grew cells in a 6-well plate to 80-90% confluency, scraped and collected the cells in PBS, spun them down and resuspended in 100uL of Tris and NaCl buffer and sonicated this. My total protein yield was only about 0.25ug of total protein per uL of lysate. Is this normal? How much protein should I expect from each well?

Thanks!

A confluent well of a 6 well plate should contain about 1 million cells which should give you somewhere between 1-10 ug of protein but this is cell type dependent.