Well it all depends on the buffer where these proteins are dissolved. There are some methods which are not compatible with detergents or chaotropic agents usually used for the extraction of membrane proteins. I think you should try BCA since it's compatible with SDS up to 5% and urea up to 3 M. Bradford and Lowry are not compatible with high SDS solutions.

Do you want to measure this in vivo on intact cells or can you prep the proteins? What technical equipment do you have available (it won't make sense to propose a technique where you don't have the right equipment)?

If you just want to measure protein content of a solution a simple test like Bradford or BCA (if you have detergents in your solution) should be enough.

Did U check Bradford assay?

if your protein is pure you can use simple nanodrop/ by measuring the UV absorbance in spectrophotometer and calculate the concentration with the extinction co-efficient of that particular protein.

If the protein is a mixture then I would go with bradford's assay or similar techniques.

Nanodrop measures the protein concentration exciting tryptophan at 280 nm, which means the concentration changes according to number of tryptophans in the sample. You can use it for a quick scan just to have an idea, but if you have protein in solution and you are looking for the exact concentration, in my opinion you should use the BCA method. For example http://www.piercenet.com/browse.cfm?fldID=02020101

The kjeldahl method is the best analytical test to determine the concentration of proteins, but if you have not instruments to perform it, try with Bradford assay.

Bradford assay should work for you.

Try using Bradford assay or BCA. Compared to all other methods these methods have less disadvantages and with some degree of accuracy you measure your protein concentration.

All the best for your experiments!

For sure, either you use Lowry assay or Bradford assay, one of these assays will quantitate your protein concentration to the standard and will give you your protein concentration rate. Best of luck

Well it all depends on the buffer where these proteins are dissolved. There are some methods which are not compatible with detergents or chaotropic agents usually used for the extraction of membrane proteins. I think you should try BCA since it's compatible with SDS up to 5% and urea up to 3 M. Bradford and Lowry are not compatible with high SDS solutions.

In my opinion kjeldahl method is not sultable for plant membrane...... The there a few oher methods but i m nt sure if it is suitable for plante membrane like lowry's method or bradford method

http://www.labome.com/method/Protein-Quantitation.html

For the easy & standard approach both Bradford and BCA assay are working fine for me. But it is always important to check the assay's compatibility with different chemicals in your lysis buffers. As already mentioned here, Bradford assay is not well compatible with (high) concentrations of SDS or UREA. The BCA assay doesn't like chelators like EDTA (>10 mM) or EGTA (the latter one is not compatible at all).

Calcareous corpuscles are a characteristic structure found in larval and adult stage cestodes. These corpuscles are known to contain several protein components and to possess protein-binding activity. However, the proteins bound to calcareous corpuscles in situ have not been studied. The present study was undertaken to identify the proteins on calcareous corpuscles. A total of 20 protein molecules were detected in gel, with major bands at 56, 53, 46, 40, 35, 29, 28, 24.5, 21, 19, 16, 13, 10 and 8 kDa. In particular, the proteins corresponding to the 21 and 16 kDa bands were most abundant. Our results demonstrated for the first time the protein contents of the calcareous corpuscles of spargana. Further studies on the functions of these proteins are required.

If you have transmembrane proteins, you probably use some detergent in your buffer. Bradford is not compatible with that so you'll have to use other method like BCA.

its depend on < which range protein u want to detect. Previously describe methods are uses for specific purpose..

I think BCA is the way to go, especially if you have lipids in your sample.

Bradford method is simple and quite reliable for estimating proteins from plant membrane rafts.

Go for BCA first since it sustains SDS, which you may want to use to solubilize your membrane proteins. MInd you should avoid using DTT for BCA. Bradford is not the same, it is sensitive to both SDS and BCA, although there may be appropriate modifications - search for them in i-net.

Do you need an accurate measure of concentration? IF you need a rough estimate, you could run it on an SDS-PAGE gel along with a ladder and protein of known concentration and size. I've never worked with plant proteins so I don't know if this is feasible.... anyone?

If these are purified proteins OD280 or Lowry mthod will serve the purpose. You do not need andy advanced method for protein estimation. If it is impure then you have to purify first by any of the standard methods and then determine the concentration

I think you should use Bradford method for this case.

I recently extracted total proteins including membrane proteins from stem cells and used BCA assay for quantification. Make sure that you use all protease inhibitors in the process because they act very fast and will ruin your lysate.

Any protein determination method inluding Bradford is OK for the purpose intended

BCA should be fine, adding phosphatase inhibitor would be advisable too

Bradford and BCA are ok for said purpose