Hi. I m currently evaluating the combined use of thiourea and urea for the extraction of total proteins from some flours. The problems I m experiencing are related to the difficulties in separating the supernatant after centrifugation (21,000 g, 15 C) in the case of the thiourea buffer (it is too viscous). Could anybody let me know if you have experienced the same problems? And, if, how could I improve my extractions?

Here is a link to a method for a protein extraction from flour. Take a look and compare to your method.

Link:http://www.ag.arizona.edu/research/larkinslab/protocols/protein%20extraction%20from%20flour.pdf

Thanks a million!
i'll have a look right now. :-))