Discussion:
Determining the subunit composition of a protein from data
Would you help me with the following problem?
You isolate a new protein. Column chromatography, in Tris-HCl buffer pH 7.4, demonstrates that this protein has a molecular weight of 110,000 D. Chromatography in the presence of 6 M guanidine hydrochloride demonstrates two peaks with masses of approximately 13,000 and approximately 26,000 D. The peak at approximately 26,000 D contains 80.3%, by mass, of the protein. The protein from this peak, when analyzed using isoelectric focusing column chromatography demonstrates that this peak contains two different proteins, each being 50% of the mass of this peak and both with acidic pIâ??s. These two 26,000 D proteins are separately treated with a^-mercaptoethanol and analyzed by column chromatography in the presence of 6 M guanidine hydrochloride. This demonstrates equal amounts of three peptides with molecular weight of 10,000 D, 9,000 D, and 7,500 D for one protein and 17,500 and 9,000 for the other protein. From these data, determine what the composition of this new protein is.