Chapter 5: Q5_2CP (page 109)
Describe how a protein may be quantified by an assay or by absorbance spectroscopy.
A protein may be quantified by observing the rate of product formation by coupled enzyme assay, radioimmunoassay (RIA), and enzyme-linked immunosorbent assay (ELISA).
Over 30 million students worldwide already upgrade their learning with Vaia!
All the tools & learning materials you need for study success - in one app.
Get started for free
Explain how you would use salting out to prepare a more concentrated solution of a protein.
It has been hypothesized that early life-forms used only eight different amino acids to build small peptides. How many different 10-residue peptides could be constructed from eight amino acids?
Treatment of a polypeptide with 2-mercaptoethanol yields two polypeptides:
1. Ala–Val–Cys–Arg–Thr–Gly–Cys–Lys–Asn–Phe–Leu
2. Tyr–Lys–Cys–Phe–Arg–His–Thr–Lys–Cys–Ser
Treatment of the intact polypeptide with trypsin yields fragments with the following amino acid compositions:
3. (Ala, Arg, Cys2, Ser, Val)
4. (Arg, Cys2, Gly, Lys, Thr, Phe)
5. (Asn, Leu, Phe)
6. (His, Lys, Thr)
7. (Lys, Tyr)
Indicate the positions of the disulfide bonds in the intact polypeptide.
You wish to sequence the light chain of a protease inhibitor from the Brassica nigra plant. Cleavage of the light chain by trypsin and chymotrypsin yields the following fragments. What is the sequence of the light chain?
Chymotrypsin
1. Leu–His–Lys–Gln–Ala–Asn–Gln–Ser–Gly–Gly–Gly–Pro–Ser
2. Gln–Gln–Ala–Gln–His–Leu–Arg–Ala–Cys–Gln–Gln–Trp
3. Arg–Ile–Pro–Lys–Cys–Arg–Lys–Phe
Trypsin
4. Arg
5. Ala–Cys–Gln–Gln–Trp–Leu–His–Lys
6. Cys–Arg
7. Gln–Ala–Asn–Gln–Ser–Gly–Gly–Gly–Pro–Ser
8. Phe–Gln–Gln–Ala–Gln–His–Leu–Arg
9. Ile–Pro–Lys
10. Lys
You are using ammonium sulphate to purify protein Q (pI = 5.0) by salting out from a solution at pH 7.0. How should you adjust the pH of the mixture to maximize the amount of protein Q that precipitates?
What do you think about this solution?
We value your feedback to improve our textbook solutions.
