Concept explainers
For each amino acid
a. methionine
b. serine
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ORGANIC CHEM.(LL)W/STD GDE.+CONNECT PKG
- Calculate the isoionic and dielectric pH of 0.01510 M glutamine. pk1=2.19 pk=9.0arrow_forwardFor the amino acid alanine, the major species in solution at pH 7 is the zwitterionic form, which has a negatively charged carboxylic acid group and a positively charged amino group. There is a less common neutral form in which neither group is charged. The carboxylic acid group of alanine has a p?apKa of 3.3. The amino group of alanine has a p?apKa of 8.8. Estimate the ratio of the concentration of the neutral amino acid species to the zwitterionic species at pH 7.arrow_forwardThe initial pH of a 2M arginine solution is 14. What is the predominant structure of arginine in solution at this pH?arrow_forward
- The pKa for the side chain amino group in lysine is 10.4. If we were working at physiological pH 7.4, what would be the ratio of the protonated to unprotonated versions of lysine? a. 1000:1 b. 3:1 c. 1:1000 d. 1:3arrow_forward(b) Describe how the charge of some amino groups in a protein might differ at pH 9.0 and pH 5.0. the charge on the amino group will differ at pH 5 and pH 9 which will depend on the pKa of the amino acid. (c) Describe how the charge of some carboxyl groups in a protein might differ at pH 9.0 and pH 5.0. charge on carboxyl group will differ at pH 5 and pH 9 which will depend on the pKa of the amino acid. (d) Given your answers to parts (b) and (c), what kind of intramolecular interactions in beta-galactosidase are most likely to be affected by a change in pH from 9.0 to 5.0? (e) Could the interactions you mention in part (d) affect the catalytic activity of beta-galactosidase?arrow_forward10. Use the information in the table below to draw the structure of the predominant form of each amino acid at physiological pH (pH = 7.4) R side chain pKa (a-COOH) -CH₂CH(CH3)2 -(CH2)4NH2 -(CH2)2CO2H Amino acid Leucine Lysine Glutamic acid L-leucine L-lysine L-glutamic acid 2.36 2.18 2.19 pKa (α-NH3*) pKa (side chain) 9.60 8.95 9.67 10.79 4.25arrow_forward
- 2. A. What is the pH of Deuterium at its isoelectric point? B. Show the structure of this amino acid at its isoelectric point. C. What is the charge of this amino acid in a strongly acidic solution?arrow_forwardFor aspartic and glutamic acids, the isoelectric point occurs at a pH where the net charge on the two carboxyl groups is -1 and balances the charge of +1 on the a-amino group. Calculate pI for these amino acids.arrow_forward(a) One amino acid that is likely to have a net negative charge at pH 8.(b) One amino acid that may be dehydrated with H2SO4.(c) One polar uncharged amino acid. (d) One nonpolar aromatic amino acid.(e) The nonpolar amino acid with the highest molar mass that was not previously selected.arrow_forward
- Draw a structural formula for the form of amino acid most prevalent at pH 1.0. (a) Threoninearrow_forwardIf the pH of a solution of Arginine is equal to a half of the 3 pka values of all of its functional groups, what will be the charge on the majority of the Arg molecules in that solution? Please explain. Am i supposedd to add up the three pka values and then divide it in half to find the pH? Thanksarrow_forwardOrnithine is an amino acid that is not used in the synthesis of proteins, but is an important intermediate in several metabloic pathways including the urea cycle and the synthesis of polyamines. It has a perfectly ordinary terminal amino group and terminal carboxyl group like any other amino acid (so use the pKas for those groups given on your amino acids handout), and a side chain with a single ionizable side group with a pKa of 10.3. If ornithine is placed in solution at pH 7.0, it has a net charge of +1. What would the net charge on this amino acid be if the pH of the solution was raised to pH 12.0? Please explain your reasoning.arrow_forward
- General, Organic, and Biological ChemistryChemistryISBN:9781285853918Author:H. Stephen StokerPublisher:Cengage LearningOrganic And Biological ChemistryChemistryISBN:9781305081079Author:STOKER, H. Stephen (howard Stephen)Publisher:Cengage Learning,