Two-dimensional gel electrophoresis of proteins in a cell extract provides a qualitative way to compare proteins with respect to intra- cellular abundance. Describe a quantitative approach to the deter- mination of number of molecules of an enzyme per cell.

In the Biuret Assay for protein concentration determination, the role of sodium potassium tartrate is to prevent the (gaining, losing) of electrons by Cu2+.

A biochemist discovers and purifies a new enzyme, generating the purification table below. Procedure Total protein (mg)Activity (units) 1. Crude extract 20,000 4,000,000 2. Precipitation (salt) 5,000 3,000,000 3. Precipitation (pH) 4,000 1,000,000 4. lon-exchange chromatography 200 800,000 5. Affinity chromatography 50 750,000 6. Size-exclusion chromatography 45 675,000 (a) From the information given in the table, calculate the specific activity of the enzyme after each purification procedure.

During successful purification of every enzyme, the following may be expected: Select ALL that apply. 1. Solubility in NaCl increases 2. The activity increases 3. The specificity increases 4. The number of subunits increases 5. the epitope number increases

SPR is one of many techniques to examine binding affinities of biomolecules. Choose another technique that can be used to measure binding affinity between two biomolecules, and briefly compare and contrast this technique with SPR. (Hint: think about sample requirements, the type of data produced, potential pitfalls with the techniques, etc.)

If you did not use a saturating concentration of pNPP to establish your initial calibration curve, how would your estimate for the [enzyme] in an unknown sample change?

Find a method that uses some form of HPLC for the analysis of proteins. What was the stationary phase used? How does this kind of stationary phase separate the proteins? What kind of mobile phase was used?  Was the method isocratic or was a gradient used? How were the proteins detected?

A biochemist discovers and purifies a new enzyme, generating the purification table below. Procedure Total protein (mg)Activity (units) 1. Crude extract 20,000 4,000,000 2. Precipitation (salt) 5,000 3,000,000 3. Precipitation (pH) 4,000 1,000,000 4. lon-exchange chromatography 200 800,000 5. Affinity chromatography 50 750,000 6. Size-exclusion chromatography 45 675,000 (a) From the information given in the table, caleulate the specific activity of the enzyme after each purification procedure. (b) Which of the purification procedures used for this enzyme is most effective? (c) Which of the purification procedures is least effective? (d) Is there any indication based on the results shown in the table that the enzyme after step 6 is now pure? (e) What else could be done to estimate the purity of the enzyme preparation?

The purpose of the progress curve is to determine if an enzymatic reaction rate remains constant for given concentrations of enzyme and substrate, for a given assay time (20 min). How long did the rate of reaction of WGAP remain constant in your experiments? How do you know? What would cause the reaction rate to not be constant and plateau after some time?

Explain the basis for identification using biochemical testing. – Again, discuss enzymatic pathways, how do we make enzymes in a cell, what is the blueprint for an enzyme? Please keep this answer to 2-3 sentences