(a) () The isoelectric point (pl) of the protein, i.e., the pH at which the overall electrostatic charge on the protein Σ z = 0, is 5.3. Although the pKa values in the table above are only approximate values generally characteristic of residues with unhindered exposure to solvent, confirm that the overall charge on the protein must pass through zero between pH 4 and pH 6. (b) (-: ) Estimate what must be the average pKa value of all of the residues containing carboxylic acid groups using the H-H equation below, assuming that the pKa values of the positively charged groups do not change from the values given in the table above: pH = pKa + log [base]/[acid]
(a) () The isoelectric point (pl) of the protein, i.e., the pH at which the overall electrostatic charge on the protein Σ z = 0, is 5.3. Although the pKa values in the table above are only approximate values generally characteristic of residues with unhindered exposure to solvent, confirm that the overall charge on the protein must pass through zero between pH 4 and pH 6. (b) (-: ) Estimate what must be the average pKa value of all of the residues containing carboxylic acid groups using the H-H equation below, assuming that the pKa values of the positively charged groups do not change from the values given in the table above: pH = pKa + log [base]/[acid]
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
Related questions
Question
![3. The trp repressor is a homodimer with 107 amino acid residues per monomer. The content of proton
dissociable groups of each monomer is given below:
Side chain
pKa
number/monomer
ZpH 4
ZpH 6
Arginine
Aspartate
Glutamate
12.5
9.
4.0
9.
4.0
10
Histidine
6.0
Lysine
Tyrosine
-NH3®
—СООН
10.0
9.5
7.0
1
4.0
1
(a) ('. - : --) The isoelectric point (pl) of the protein, i.e., the pH at which the overall electrostatic charge
on the protein E z = 0, is 5.3. Although the pKa values in the table above are only approximate values
generally characteristic of residues with unhindered exposure to solvent, confirm that the overall charge
on the protein must pass through zero between pH 4 and pH 6.
) Estimate what must be the average pKa value of all of the residues containing carboxylic
(b) (
acid groups using the H-H equation below, assuming that the pKa values of the positively charged
groups do not change from the values given in the table above:
pH = pKa +
log [base]/[acid]
%D](/v2/_next/image?url=https%3A%2F%2Fcontent.bartleby.com%2Fqna-images%2Fquestion%2F7e3218aa-1b65-42a2-9071-7edb43c3a555%2F6b0d3ba4-d88b-423a-ad34-349056caaa7c%2Ffnqqrx_processed.png&w=3840&q=75)
Transcribed Image Text:3. The trp repressor is a homodimer with 107 amino acid residues per monomer. The content of proton
dissociable groups of each monomer is given below:
Side chain
pKa
number/monomer
ZpH 4
ZpH 6
Arginine
Aspartate
Glutamate
12.5
9.
4.0
9.
4.0
10
Histidine
6.0
Lysine
Tyrosine
-NH3®
—СООН
10.0
9.5
7.0
1
4.0
1
(a) ('. - : --) The isoelectric point (pl) of the protein, i.e., the pH at which the overall electrostatic charge
on the protein E z = 0, is 5.3. Although the pKa values in the table above are only approximate values
generally characteristic of residues with unhindered exposure to solvent, confirm that the overall charge
on the protein must pass through zero between pH 4 and pH 6.
) Estimate what must be the average pKa value of all of the residues containing carboxylic
(b) (
acid groups using the H-H equation below, assuming that the pKa values of the positively charged
groups do not change from the values given in the table above:
pH = pKa +
log [base]/[acid]
%D
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