Yes, you can use bradford assay for protein estimation for such lysates, we use the same in our lab. There are some ready to use protein estimation kits available like cb-x protein assay by g biosciences which can be used for quick protein estimation.

Dear Alok

I recommend Bradford assay because there are no reports about interfering between NP-40 OR Tween -20 and protein assay in this method.

Also you can use the spectroscopy method by using the following formula:

Protein concentration (mg/ml)=(Absorbance 280nm *0.54)-(Abs 260nm*0.74)

Lowry method also can be used but this method is not rapid enough and has many steps but detectionlimit is good.

Bradford works fine with this type of samples. I'm currently using Bio-Rad Protein Assay Dye Reagent Concentrate (500-0006). If You would have any problems there is alternative RC DC Protein Assay Kit I (500-0121). It's quite cheap and works fine.

Regards'

BCA by Pierce also works like a charm. It is a bit longer because you need to develop the reaction at 37°C for 30 minutes but results are to my experience more reproducible.

I would not wonder to much with 0.5 or 1% of detergent, especially if you do a relative protein quantification (to run western blot or ELISA for example)

you can use 2D quant kit from GE for protein estimation kit from Biorad which are good enough fro samples having high amount of salts and detergents.

2-D quant kit also works fine. But in my oppinion, if You would't see any signs of interference Bio-Rad Protein Assay Dye Reagent Concentrate is the best choice. It's a single step reaction. I'm using it for my 2DE samples without any problems. Others RC-DC and 2-D quant kit, are time consuming ones, but working nice with high concentrations of detergents and reductants.

Thanks everyone for these valuable suggestions. Did Bradford and works fine.

I think this link is useful, 

http://www.instanano.com/characterization/theoretical/concentration-calculation-from-uv-vis-absorbance/

max 0.01% tween 20 or 0.05% tritonX100 you can use