1.
a. For the following groups, indicate their predominant ionic species (draw the chemical structure) at pH 7.4: a. The side chain amino group (–NH3+) of the amino acid lysine, pKa=10.5. The side chain carboxyl group (-COOH) of the amino acid glutamate, pKa=4.1.
b.For a buffer with a pKa of 8.03 :
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1. a. For the following groups, indicate their predominant ionic species (draw the chemical structure) at...
Knowing the information found in the table below, what is the predominant form of lysine at pH 9.5? pka of α-NH3+ pKa of side chain Amino Acid pK, of α-COOH Lysine 2.18 8.95 10.53 H3N H2N NH2 NH H2N H3N OH OH NH2 NH2
Consider the amino acid lysine: a. At physiological pH (pH = 7.4), what is the predominant form in solution? b. What percent of the side chain group is ionized at this pH? c. What percent of the carboxylic acid group is ionized at this pH?
The one-letter sequence is: WATER a) Draw the peptide (R-groups trans), indicating charges, in predominant form found at pH = 0. b) What is the isoelectric point? c) What is the average charge on the population of peptide macromolecules at pH = 2.2? d) What is the average charge on the population of peptide macromolecules at pH = 12.5? TABLE 4.1 Amino Acid Alanine Arginine Asparagine Aspartic acid Cysteine....« Glutamic acid Glutamine Glycine Histidine Isoleucine Leucine Lysine … Methionine Phenylalanine...
What about the pKa values of the R groups of the seven amino acids containing an ionizable R group? Tyr 10.5 Lys 10.5 Arg 12.5 Asp 3.9 Glu 4.1 His 6.0 Cys 8.4 Indicate the approximate net charge of each of these seven R groups at pH 7.4. Indicate the approximate net charge of each of these seven amino acids at pH 7.4. Note: remember the carboxyl and the alpha-amino group in addition to the ionizable (acidic or basic) R...
5. Amino acid titration. The graph below shows a titration of an amino acid with NaOH. This experiment reveals several important features of this amino acid. A) What is the identity of the amino acid? [Write its full name.] B) Match the following points in the titration curve. [In the space beside each description (left), write a number (1-6) corresponding to a specific pH (right).] The amino acid is fully protonated. 1) pH=0.0 PH The amino acid is fully deprotonated....
15. Which is used to reduce the disulfide bonds in proteins? D) iodoacetate B) performic acid C) DTT A) PITC 16. What is the net charge on the tripeptide Gly-Asp-Lys at pH 1.5? The table below gives the pKa's of the ionizable groups on the free amino acids. Free amino acid pK, of a-Carboxyl pKs of side chain pKa of a-amino group 2.4 group 9.8 Glycine Aspartate Lysine 2.0 3.9 9.9 2.2 9.1 10.5 A) -2 B) C) D) +2...
Amino Acids SW C2 9. Which of the following is an L-amino acid? çoo coo coo HẠN |-R HANH, HẠN –H HÀNH R coo B. 10. The following questions refer to the structures A-E below: (a) Which represents the structure of an amino acid at very high pH? (b) Which is a zwitterion? (c) Which represents the structure of an amino acid at very low pH? (d) Which structure/(s) is/are) not possible? R-CH-COOR-CH-COOH R-CH-COOH R-CH-COOR -CH-COO NH2 NH2 *NH NH2...
1,2,and 3 please!! Post-Lab Questions 1. The pKa value for the carboxylic structure of acetic acid at (a) pH- 1, (b) pH-7, and (c) p-13 acid group in acetic acid is 4.75. Write the predominant 2. Fill in the following table to show the theoretical results for the titration of 1.0 L of 0.20 M acetic acid by adding the designated amount of solid (no volume change) potassium hydroxide, KOH. Show a sample calculation of your work below. pH IH'T...
STRUCTURE WILL VARY DEPENDING IF PKA IS LARGE OR SMALL, Draw a formula for Val-Ser-Gly (V-S-G) in its predominant ionic form at pH 7.3. You may assume for the purposes of this question that the pKa values of the acidic groups of amino acid residues in the peptide are the same as in the amino acid itself. You do not have to consider stereochemistry. You do not have to explicitly draw H atoms. Do not include lone pairs in your...
What is the approximate net charge of the following pentapeptide at pH 10? Arg-Gln-Cys-His-Ala What is the Isoelectric point (pI) of the peptide given above? Use the pKa values given here when needed: Side group/ amino acid pKa Asp 3.9 Glu 4.1 HIs 6.0 Cys 8.4 Tyr 10.5 Lys 10.5 Arg 12.5 C-term 3.5 N-term 9.0