Biochemistry Questions
1) A peptide, KKDSRHSTTR is tightly bound to a negatively charged ion exchange column. The column is washed with a pH 7.2 HEPES buffer (50 mM) and the peptide does not elute. Suggest two ways that you can change the buffer that will make the peptide elute from the column.
2) What amino acid(s) is/are involved in crosslinking polypeptide chains. How can these crosslinks be cleaved and prevented from reforming?
3) A polypeptide is subjected to the following degradative techniques results in polypeptide fragments with the indicated amino acid sequences. What is the amino acid sequence of the entire polypeptide? A) Trypsin digestion: 1) Gln-Met-Lys 2) Gly-Met-Asp-Ile-Lys 3) Phe-Ala-Met-Lys 4) Tyr-Arg B) Cyanogen bromide treatment: 5) Asp-Ile-Lys-Gln-Met 6) Lys 7) Lys-Phe-Ala-Met 8) Tyr-Arg-Gly-Met
4) While on an expedition to the Amazon jungle, you isolate a polypeptide you suspect of being the growth hormone of a newly discovered species of giant spider. Unfortunately, your portable sequenator was so roughly handled at the airport that is refuses to provide the sequence of more than four consecutive amino acid residues. Nevertheless, you persevere and obtained the following data: Hydrazinolysis: Val Dansyl chloride treatment followed by acid hydrolysis: Dansyl-Pro Trypsin digestion followed by Edman degradation of the separated fragments: Gly-Lys Phe-Ile-Val Pro-Gly-Ala-Arg Ser-Arg
A) Provide as much information as you can concerning the amino acid sequence of the polypeptide.
B) Considering the poor condition of you sequenator, what additional analytical technique would most conveniently permit you to complete the sequence determination of the polypeptide?
C) Suggest two ways that you would use to separate the tryptic peptides mentioned above if you needed large quantities of each peptide. If you needed only analytical quantities of the peptides.
5) A heptapeptide when treated
2) What amino acid(s) is/are involved in crosslinking polypeptide chains. How can these crosslinks be cleaved and prevented from reforming?
3) A polypeptide is subjected to the following degradative techniques results in polypeptide fragments with the indicated amino acid sequences. What is the amino acid sequence of the entire polypeptide? A) Trypsin digestion: 1) Gln-Met-Lys 2) Gly-Met-Asp-Ile-Lys 3) Phe-Ala-Met-Lys 4) Tyr-Arg B) Cyanogen bromide treatment: 5) Asp-Ile-Lys-Gln-Met 6) Lys 7) Lys-Phe-Ala-Met 8) Tyr-Arg-Gly-Met
4) While on an expedition to the Amazon jungle, you isolate a polypeptide you suspect of being the growth hormone of a newly discovered species of giant spider. Unfortunately, your portable sequenator was so roughly handled at the airport that is refuses to provide the sequence of more than four consecutive amino acid residues. Nevertheless, you persevere and obtained the following data: Hydrazinolysis: Val Dansyl chloride treatment followed by acid hydrolysis: Dansyl-Pro Trypsin digestion followed by Edman degradation of the separated fragments: Gly-Lys Phe-Ile-Val Pro-Gly-Ala-Arg Ser-Arg
A) Provide as much information as you can concerning the amino acid sequence of the polypeptide.
B) Considering the poor condition of you sequenator, what additional analytical technique would most conveniently permit you to complete the sequence determination of the polypeptide?
C) Suggest two ways that you would use to separate the tryptic peptides mentioned above if you needed large quantities of each peptide. If you needed only analytical quantities of the peptides.
5) A heptapeptide when treated