Consider the following peptide:
Cys-Arg-Pro-Asp-Thr-Leu-His-Lys-Gln-Glu-His
How is the peptide different at pH = 6
and pH 8? Which of the two pHs would you use to run an ion exchange
column, and would you choose anion or cation exchange?
The amino acid sequence of human adrenocorticotropin, a
polypeptide hormone, is:
Ser-Tyr-Ser-Met-Glu-His-Glu-Arg-Trp-Gly-Lys-Pro-Val-Gly-Lys-Lys-Arg-Arg-Pro-Val-Lys-Val-Tyr-Pro-Asp-Ala-Gly-Glu-Asp-Gln-Ser-Ala-Glu-Ala-Glu-Pro-Leu-Glu-Phe
a)What is the approximate net charge of this molecule at pH 3? ph
7? ph 9? Assume that the pKs of the terminal -NH3+ and -COOH groups
are 7.8 and 3.6, respectively.
Determine which of these four peptides is most likely to become
a beta sheet.
Met-Leu-Lys-Ala-Ser-Ala-Leu-Glu-Lys-Leu-Ser-Glu
Ala-Glu-Met-Leu-Gln-Lys-Arg-Gly-Cys-Gly-Asp-Glu
Lys-Thr-Val-Ile-Trp-Pro-Phe-Tyr-Ile-Gln-Ile-Gly
Arg-Ser-Tyr-Glu-Gly-Leu-Lys-Arg-Ile-Ala-Glu-Ser
I would like help with the question but also I would like to
know what makes a peptide more likely to form a beta sheet over and
alpha helix and vice versa.
1 (met) 2 (asp) 3 (gly) 4 (glu) 5
(trp)
The following pentapeptide MET-ASP-GLY-GLU-TRP is initially
treated with cyanogen Bromide, and subsequently treated with
Chymotrypsin. Based on this information, answer the following:
Identify the carboxyl and amino terminus of the pentapeptide before
treatment and indicate if terminal side chain groups are ionizable?
If applicable, indicate which reagents result in chemical cleavage
or enzymatic cleavage. Biochemical approaches can be used to
determine the differences in the peptide before and after
treatment....
Look at this undecapeptide: Arg Asp Cys Glu Leu Lys Met
Phe NH4+. What would each step do to the udecapeptide?
Draw the final structure.
a. treatement with iodoacetate that had no
affect on the undecapeptide.
b. treatment with 2 x 2-mercaptoethanol
yielding a tripe-tide and octapeptide.
c. treatment with carboxypeptidase A liberated
leucine.
d. treatment with cyanogen bromide yielding a
methionine, a tripeptide and a heptapeptide.
The question states that these amino acids are only some
components of the...
Examine the tripeptide below:
Lys-Glu-Asp
Calculate the isoelectric point (pI) of this tripeptide. You
can assume that the pKa of the amino terminus is 9.06 and the pKa
of the carboxy-terminus is 1.99.
a. 2.95
b. 3.99
c. 5.53
d. 6.48
e. 7.31
56. Hypocapnia:
Select one:
a. would result in an increase in blood pH.
b. would not affect the rate and depth of breathing.
c. may occur in a patient with COPD.
d. usually occurs in conjunction with reduced respiratory
rates.
e. Is caused by poor oxygen uptake.
A negatively charged sample would be expected to migrate towards
the anode (positively charged electrode). How then is it that
species of all charges are detected in capillary electrophoresis at
the cathode (negatively charged) end of the system