What is the net charge of the following amino acids (A, B, C, D) at pH 5.96 ? Amino acid Isoelectric point Net charge at pH 5.25 A. 10.76 O+1 00 0-1 B 7.59 O+1 00 0-1 3.00 O+1 00 0-1 5.96 O+1 00 0-1

The pka of the side chain of histidine is 6.00. What is the percent of protonated histidine at pH 6.4? 15.3% 28.5% 45.3% O 66.6%

1.0.1 mL of a protein solution of concentration of 11 mg/mL was diluted to a total volume of 4.0 mL with water (i.e. 0.1 mL of the solution was added to 3.9 mL of water). 2 mL of this solution was then mixed with 18 mL of water. What is the concentration of the diluted protein solution? Space to show your workings:

At which pH would the peptide with the amino acid sequence 'KEYHR' be found in an IPG (Immobilized pH gradient) strip after successful isoelectric focusing. Show calculation. lonizable groups Alpha amine group of K Side chain group of K Side chain group of E Side chain group of Y Side chain group of H Side chain group of R Alpha carboxylic acid group of R pka 8.95 10.53 4.25 10.07 6 12.48 2.17

The amino acid arginine ionizes according to the following scheme: (a) Calculate the isoelectric point of arginine. You can neglect contributions from form I. Why? (b) Calculate the average charge on arginine when pH = 9.20. (c) Is the value of average charge you calculated in part b reasonable, given the pI you calculated in part a? Explain your answer

A protein has an asp glu/arg lys ratio of 3. Explain how would the overall charge on this molecule likely be at pH 7 be negative?

32) You are working with an molecule with a pl of 6.00 and the pKa's of the ionizable groups on the molecule are 1.3, 4.1 and 7.9. You would like this amino acid to have a net negative charge. Which of the following pH values would result in a net negative charge? A) 1.3 B) 4.1 C) 4.43 D) 6.0 E) 7.9

Can you please explain how to solve this problem?

the overall, net ionic charge on this peptide at pH = 7 would be: Cys - Ala - Glu-Arg - Met - Ser

A protein has a dissociation equilibrium constant equal to 4.0um. What is the concentration of free ligand when the fraction of bound sites is 0.7