Q5. Each ionizable group of an amino acid can exist in one of two states, charged or neutral. Theelectric charge on the functional group is determined by the relationship between its pka andthe pH of the solution. This relationship is described by the Henderson-Hasselbalch equation.(a) Histidine has three ionizable functional groups. Write the equilibrium equations for its threeionizations and assign the proper pKa for each ionization. Draw the structure of histidinein each ionization state. What is the net charge on the histidine molecule in each ionizationstate?(b) Draw the structures of the predominant ionization state of histidine at pH 1, 4, 8, and 12.Note that the ionization state can be approximated by treating each ionizable groupindependently.(c) What is the net charge of histidine at pH 1, 4, 8, and 12? For each pH, will histidine migratetoward the anode (+) or cathode (-) when placed in an electric field?

Amino acids are simply an alpha-carbon bonded to 4 groups. The 4 groups are;an alpha-carboxyl group…

Answered: Q5. Each ionizable group of an amino…

Biochemistry

9th Edition

ISBN:9781319114671

Author:Lubert Stryer, Jeremy M. Berg, John L. Tymoczko, Gregory J. Gatto Jr.

Publisher:Lubert Stryer, Jeremy M. Berg, John L. Tymoczko, Gregory J. Gatto Jr.

Chapter1: Biochemistry: An Evolving Science

Section: Chapter Questions

Problem 1P

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1. Isoelectric point of polypeptide: (1) is pH at which the o-carboxyl and o-amino groups are uncharged. (2) is pH at which the net charge on the molecules in solution is 0. (3) is pH at which the charge of the o-carboxyl group is higher than the charge of the o- amino group. А. (1) only В. (2) only С. (3) only D. (1) and (3) E. (2) and(3)
5. Refer to Model 2 for information relevant to this question. A sample of the peptide Lys-Glu-Ser has a net charge of zero between what two pH values? What is the pl of Lys-Glu-Ser? Model 2: The pl of a peptide is determined by examining the ionizable groups. The protonated and unprotonated forms of each ionizable group are in equilibrium. Consider the peptide Lys-Glu-Ser shown below at pH 7.2. The complete structure is on on the left and a stylized structure with just the ionizable groups is on the right. While the N-terminal is depicted as protonated, a sample of Lys-Glu-Ser is composed of a population of molecules and within that population some molecules contain a non-protonated N-terminal group at pH 7.2. may H3N* COO- H3N-CH-CIN-CH C N-CH C- H. pK 3.5 OH H. pK= 8.5 COO- CH2 CH2 CH2 NH, pK 10.0 pK 4.2 CH2 CH2 OH CH2 c=0
1. Examine the synthetic glycoprotein, Molecule A, shown below: Protein- OH OH OH OH OH ÓH OH Molecule A OH Draw the structures of the products obtained when Molecule A reacts under the following conditions. Justify your answer. If no reaction occurs, explain why. The monosaccharide rings that have not reacted may be represented by an “R" group. Mechanisms are not required. (а) Ammonium Carbonate, 5 days. (b) Excess Sodium Periodate. (c) 2,3-dinitrophenyl hydrazine under reductive amination conditions. NO2 O2N. „NHNH2 2,3-dinitrophenyl hydrazine
Can you please explain how to solve this problem?
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
1. Make a series (at least 3) of drawings to show the three dehydration synthesis reactions that take place between the two Fatty Acids, the Phosphate Head and the Glycerol. Show the water molecules made. a) Label the following on the completed phospholipid: hydrophilic and hydrophobic parts of the molecule, fatty acids, phosphate group, and glycerol. b) Compare the structure of the phospholipid to that of a triglyceride. How are the two molecules Similar? How are they different? 2. Use the following vocabulary to label and draw a cell membrane: cytoplasm (cell lumen) extra-cellular fluid hydrophobic hydrophilic polar head non-polar tails a) How many O-H groups are there? And are the O-H areas of sucrose polar or non-polar? b) What is the term that is used to discuss how tightly or loosely an atom's nucleus has a hold of its valence electrons?
4 This is a three-part question about a tripeptide. Answer all three sub-questions. The pKR of side chains of Tyr, and Lys is 10.46 and 10.54 respectively. The molecular weight of amino acids Ala, Lys, and Tyr in neutral form is 89.1, 146.2, and 181.2 Da, respectively. 1) Draw the chemical structure of the dominant form of tripeptide AKY at pH = 11.5, ensure you have the correct stereochemistry and ionization state of each functional group (Hint, lysine has a C-epsilon as the furthest carbon from C-alpha). 2) Calculate the pI of tripeptide AKY, assuming the terminal amino group has a pKa of 8.0, and the terminal carboxyl group has a pKa of 3.5 3) Calculate the molecular weight of AKY at pI
2. | Calculate the overall charge (pH 7) on the following three polypeptides and answer the questions below. Assume the following pKa values: N-terminal –NH3®, 7.0; all -COOH groups, 4.0; Arg, 12.5; Cys, 8.4; His, 6.0; Lys, 10.0; Tyr, 10.0. (A) Ser-Tyr-Ser-Met-Glu-His-Phe-Arg-Trp-Gly-Lys–Pro–Val–Gly–Lys–Lys–Arg-Arg-Pro-Val-Lys–Val-Tyr-Pro-Asp-Ala -Gly- Glu-Asp-GIn– Ser-Ala-Glu-Ala-Phe-Pro-Leu-Arg-Glu-Phe (B) Ser-Tyr-Ser-Met-Glu-His-Phe-Arg-Trp-Gly-Ala-Pro-Val-Gly-Glu-Glu–Cys-Asp-Pro-Val-Glu–Val–Tyr-Pro-Asp- Ala-Gly-Glu-Asp-Gln-Ser-Ala-Glu-Ala-Phe-Pro-Leu-Glu-Phe-Cys-Ser-Tyr-Ser-Met-Glu–His-Phe-Asp-Trp-Gly- Asp-Pro-Val-Gly-Pro-Asp-Ala-Gly-Asp-Gln-Pro-Val–Gly–Glu-Glu-Cys-Asp-Pro–Val-Glu–Val–Tyr-Pro-Asp-Ala (C) Gly-Ser-Val-Arg-Asp-Pro-Val-Lys-Glu-Val-Tyr-Pro-Asp- Lys–Ala-Gly-Arg-Glu-Ser-Arg-Ala (d) Which of the three peptides would migrate the closest to the anode in isoelectric focusing? (e) Which of the above peptides would elute last from a gel filtration column? (f) Which of the three…
20. The dissociation constant of protein Z for ligand Y is: 10 micromolar. What fraction of the ligand is bound at ligand concentration = 5 micromolar?
3
5 You need to separate the following three proteins, Protein A (MW 76 600 Da; pI 4.5); Protein B (MW 70 000 Da and pI 8.2) and Protein C (MW 42 000; pI 8.6). Describe what column/s you would use, the pH of the buffer/s you would use, which proteins are retained on the column and how you would elute the bound protein/s. How would you monitor where the protein peaks elute and whether the protein in each peak is pure of not?
Explain what the meaning of these distances is (e.g., from where to where?)Crystal structure of human monocyte chemotactic protein-2

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