Problem 2
Product Concentrations A \(10^{-3} \mathrm{M}\) solution of gamma globulin (antibodies) is called a "concentrated solution." Why is it called a concentrated solution? Support your answer with a calculation.
Problem 3
pH-Dependent Change of Conformation of Poly-L-glutamic Acid A synthetic polypeptide made up of L-glutamic acid residues is in a random coil configuration at pH 7.0 but changes to ? helical when the pH is lowered to 2.0. Explain this pH- dependent conformational transition.
Problem 8
Calculations for the Purification of a Recombinant Protein The purification of a recombinant protein is carried out starting with 100 liters of a clarified cell lysate (i.e., the cells have been lysed, and the cell debris has been removed to give a clarified solution), which has a total protein concentration of \(0.36 \mathrm{mg} / \mathrm{ml}\) and a recombinant protein concentration of \(2.2 \mathrm{U} / \mathrm{ml}\), where U denotes units of biological activity of the recombinant protein. It is known that the completely pure recombinant protein has a specific activity of \(40.0 \mathrm{U} / \mathrm{mg}\). Purification is continued until a chromatography step that yields \(2.0\) liters of a fraction containing the protein, with a total protein concentration of \(1.11 \mathrm{mg} / \mathrm{ml}\) and a recombinant protein concentration of \(43.2 \mathrm{U} / \mathrm{ml}\).For the recombinant protein, calculate the starting and ending purity, the starting and ending specific activity, and the percentage yield and fold purification through the chromatography step.
Problem 9
Process Synthesis A process for isolating an antibody against insulin has, as a unit operation, the reaction of the antibody with the antigen in a continuous-stirred tank reactor. The reaction product is a precipitate that is continuously removed from the reactor with \(10 \%\) of the solution, which is mouse serum. Since insulin is an expensive reagent, only stoichiometric amounts can be added to the mouse serum, which contains \(8 \mathrm{mg} / \mathrm{liter}\) of anti-insulin. If this particular monoclonal antibody precipitates with its antigen in a \(1: 1\) ratio, how many milligrams of insulin must be added to the reactor per hour to process \(100 \mathrm{ml}\) of mouse serum per hour? (Assume that equilibrium is achieved in this reactor.) Sketch a flowchart of this process.
Problem 10
Product Concentrations Using the Handbook of Biochemistry and Molecular Biology (G. Fasman, ed., CRC Press, Cleveland, 1976) or a similar source or a suitable biochemistry textbook (in other words, looking up information), find the necessary information to determine the amount of material required to make \(1 \mathrm{ml}\) of each of the following aqueous solutions: (a) \(0.01 \mathrm{M}\) cytochrome \(\mathrm{c}\) (b) \(1 \times 10^{-7} \mathrm{M} \beta\)-galactosidase (c) \(0.01 \mathrm{M}\) porcine insulin (d) \(0.01 \mathrm{M}\) human hemoglobin (e) \(0.1 \mathrm{M}\) streptomycin (f) \(1 \times 10^{-6} \mathrm{M}\) oligonucleotide with 10 nucleotides Also calculate the concentrations in terms of the following additional standard means of expressing bioproduct concentrations: percent (weight per volume) and milligrams per milliliter. Assuming that the solutions are in pure water, also express the concentrations as mole fractions. Discuss the feasibility of making each one of these solutions.
