A protein has a molecular mass of 400 kDa when measured by size-exclusion chromatography. When subjected to gel electrophoresis in the presence of sodium dodecyl sulfate (SDS), the protein gives three bands with molecularmasses of 180, 160, and 60 kDa. When electrophoresis is carried out in the presence of SDS and dithiothreitol, three bands are again formed, this time with molecular masses of 160, 90, and 60 kDa. Determine the subunit composition of the protein.

Make a table with a scale of absorbance and the concentration of protein in Chromatin sample from the following data for excel graph Absorbance=660nm following data are of tubes with concern  A =0 B=0.036 C=0.011 D=0.001 E=0.027 F=0.020 G=0.032 H1=0.176 H2=0.183 I1=0.150 I2=0.171 also plot the graph??

The SDS-PAGE gel matrix used to separate proteins by electrophoresis is composed of: A) Nitrocellulose B) Polyacrylamide C) Agarose

Is an SDS-PAGE gel, what characteristic is used to separate the proteins?  Which proteins move quickly? Which ones move slowly?

(b) Both laboratories used 10 micrograms of protein each in their kinetic assays. Protein concentrations weredetermined by the Bradford protein assay. Assay conditions employed in the two labs (pH, temperature,etc.) were also identical. What would be the most plausible cause for the discrepancy in the Vmax valuesfor the compound I? Explain.Recall that the Bradford assay measures total protein amounts in sample solution based on complexformation between a dye and proteins. Also, the assay solution used in both labs does not contain anyinhibitors.

Gradient PAGE uses differing gel concentrations along the length of the gel to achieve optimalseparation of proteins of a wide range of molecular weight proteins. How does the staining pattern of these types of gels differ from nongradient PAGE?

A number of techniques can separate proteins on the basis of their differences in mass. Describe the use of two of these techniques, centrifugation and gel electrophoresis. The blood proteins transferrin (MW 76 kDa) and lysozyme (MW 15 kDa) can be separated by rate zonal centrifugation or SDS-polyacrylamide gel electrophoresis. Which of the two proteins will sediment faster during centrifugation? Which will migrate faster during electrophoresis?

Are all the proteins separated properly using two-dimensional (2D) gel electrophoresis? Why or why not?

The purification continues with a cation exchange step in which the positively charged cytochrome C protein is separated from negatively charged DNA and other proteins. The cation exchange eluate (volume of solution collected) had a total volume of 42.0 mL and a 1.0 mL aliquot was set aside for further analysis. The following data was obtained from the 1.0 mL aliquot to quantify the protein amount and purity: The absorbance at 410 nm of the aliquot was diluted 5-fold was 0.474 (1 cm pathlength). The absorbance at 595 nm from a 1.0 mL Bradford Assay solution that was diluted by 100-fold from the aliquot was 0.195 (1 cm pathlength). Using the information given, Calculate the total protein amount in mg from the absorbance at 595 nm. Calculate the cytochrome C amount in mg from the absorbance at 410 nm using Beer’s Law.

A researcher isolates a new protein and finds that it contains 0.755% serine by weight upon amino acid analysis. The molecular mass of serine is 105 g.mol-¹. What is the minimum molecular mass for the protein assuming only one Ser residue per protein molecule? mmin = The researcher estimates the molecular mass of the protein using gel electrophoresis. From this estimated molecular mass, the researcher concludes the protein contains 3 Ser residues. What is the estimated molecular mass of the protein as shown by gel electrophoresis? g.mol-¹ mest = g.mol-1