This is the third time I am posting this question and I real

This is the third time I am posting this question and I really hope somebody can help me with this. If you are not sure please leave it to others. Thank you

A) is that because proteins may have different sizes so the bands are in different positions

B) which protein is it ?

C) which protein is it?

D ) what are the names of the other two proteins?

You are interested in integral membrane proteins of the plasma membrane. You treatments western blotting 4 individual proteins isolated after the following CONTROL: From untreated cells SET 1: Intact cells treated with a protease enzyme. SET 2: cells made permeable to proteins by treatment with small amounts of detergent before treatment with the protease. Four different proteins (W.X, Y and Z) are analyzed on SDS-PAGE Why do the bands in the \"C\" lanes run with different mobilities? which protein is exposed only on the exterior of the cell? Explain. Which protein is exposed in the interior AND the exterior of the cell? Explain. What is the minimum size (in kD) of this protein? What can you say about the other two proteins in terms of topology? Markers in Kilodaltons C 1 2 C 1 2 C 1 2 C 1 2 115 62 50/48 37 15

Solution

The proteins in the C lanes run with different mobility because, they have different molecular weights and charge. If molecular weights of proteins have been same, then depending upon their charge, the proteins show differential migration rates. SDS makes the proteins linear with uniform charge which has to be run in an electric field. So, proteins in an electric field migrate towards the positive anode at different speeds based on the molecular weight of the protein. Within the gel, high molecular weight proteins move slowly and low molecular weight proteins migrate at a faster rate and will reach the bottom of the gel. W has been showing higher molecular weight and Y has been showing lower molecular weight protein. Y has been showing high affinity to SDS, Y protein might be highly hydrophobic and shows faster migration. W has been showing slower migration rate, W protein has been showing low binding to SDS and these W proteins have been highly glycosylated. So, Y protein is in interior and W protein is exterior of the cell. The other two proteins, X, Z have been embedded between W...and Y. exterior............W.........X,Z............Y............interior.