Determination of protein molecular weights in denaturing solvents using glyceryl-CPG

Glyceryl-CPG is controlled-pore glass whose surface has been chemically modified to block its slight negative charge in aqueous solution. In contrast to normal controlled-pore glass, glyceryl-CPG can be used successfully for gel filtration of proteins in a variety of denaturing solvents, viz., 8 M urea, 6 M guanidine hydrochloride, and 0.1% sodium dodecyl sulphate. It has been found that glass with a mean pore diameter near 35 nm is suitable for the molecular weight range 17,000-100,000. Glyceryl-CPG with a smaller pore diameter is more satisfactory for molecular weights below 30,000. The stable pore size and bed dimensions of controlled-pore glass allows comparison of the conformation of a particular protein in different solvents to be made with the same column.