(a)
Interpretation:
The peptides obtained from the cleavage of given peptide chain by carboxypeptidase A has to be given.
Concept introduction:
Amino acids are linked each other by peptide bonds is called protein (one or more peptide bonds). Peptide bonds are amide bonds, in which carbonyl group of one amino acid bonded to amino group of other amino acid. The chain of the protein is drawn in such a way that left end is occupied by free amino group (say N-terminal) and right side of the chain is occupied by carbonyl group (say C-terminal).
Exopeptidases cleave peptide bonds that are not at the end.
Carboxypeptidase A is an exopeptidase, which cleave the peptide bond of C-terminal amino acid except arginine and lysine.
(b)
Interpretation:
The peptides obtained from the cleavage of given peptide chain by cyanogen bromide has to be given
Concept introduction:
Amino acids are linked each other by peptide bonds is called protein (one or more peptide bonds). Peptide bonds are amide bonds, in which carbonyl group of one amino acid bonded to amino group of other amino acid. The chain of the protein is drawn in such a way that left end is occupied by free amino group (say N-terminal) and right side of the chain is occupied by carbonyl group (say C-terminal).
Cyanogen bromide cleaves the C-terminal peptide of Methionine in a peptide chain.
(c)
Interpretation:
The peptides obtained from the cleavage of given peptide chain by trypsin has to be given.
Concept introduction:
Amino acids are linked each other by peptide bonds is called protein (one or more peptide bonds). Peptide bonds are amide bonds, in which carbonyl group of one amino acid bonded to amino group of other amino acid. The chain of the protein is drawn in such a way that left end is occupied by free amino group (say N-terminal) and right side of the chain is occupied by carbonyl group (say C-terminal).
Endopeptidases cleave peptide bonds that are not at the end.
Trypsin is an endopeptidase, which cleave the C-side peptide bond of positively charged side chains such as arginine and lysine.
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Chapter 17 Solutions
Essential Organic Chemistry (3rd Edition)
- In a paragraph form provide the experimental procedure of the reaction of oxazetidine-containing peptides and α-ketoacid that will result in protein that contain native serine residuesarrow_forwardThrough acid hydrolysis for 24 hours, Jackson obtained the following amino acid residues: Ala-Arg-Cys-Gln-Lys-Phe-Tyr-Val No phenylthiohydantoin structure was obtained after Edman analysis. Furthermore, no C-terminal residue was also obtained after treatment with carboxypeptidase. He then used trypsin and chymotrypsin enzymes as cleaving agents. Trypsin cleaves at the C-terminal of basic amino acids Lys and Arg while chymotrypsin cleaves at the C-terminal of aromatic amino acids such as Phe, Tyr, and Trp. The results of trypsin and chymotrypsin cleavage were listed in the table below: Enzyme Amino Acid Residues Chymotrypsin Trypsin Determine the sequence of the polypeptide using the one-letter code of the amino acids. Kindly check the lecture slide for the amino acid one-letter codes. Drag the correct boxes to their respective markers. The directionality of the N-to-C terminals is also specified below. N-terminal Val-Lys-Ala-Phe + Gln-Arg-Cys-Tyr Cys-Tyr-Val-Lys + Ala-Phe-Gln-Arg I…arrow_forwardDetermine the primary structure of an octapeptide from the following data: Acid-catalyzed hydrolysis gives 2 Arg, Leu, Lys, Met, Phe, Ser, and Tyr. Carboxypeptidase A releases Ser. Edman’s reagent releases Leu. Treatment with cyanogen bromide forms two peptides with the following amino acid compositions: 1. Arg, Phe, Ser 2. Arg, Leu, Lys, Met, Tyr Trypsin-catalyzed hydrolysis forms the following two amino acids and two peptides: 1. Arg 2. Ser 3. Arg, Met, Phe 4. Leu, Lys, Tyrarrow_forward
- 60 61 62 63 The peptide KNYPEH N-terminal amino group has a pKa of 8.6 and the C-terminal carboxylate group has a pKa of 4.5. What is the net charge of this peptide at a pH of 1? Type your answer... The peptide KNYPEH N-terminal amino group has a pKa of 8.6 and the C-terminal carboxylate group has a pKa of 4.5. What is the net charge of this peptide at a pH of 7? Type your answer... The peptide KNYPEH N-terminal amino group has a pKa of 8.6 and the C-terminal carboxylate group has a pKa of 4.5. What is the net charge of this peptide at a pH of 15? Type your answer... The peptide KNYPEH N-terminal amino group has a pKa of 8.6 and the C-terminal carboxylate group has a pKa of 4.5. What is the isoelectric point of this peptide? Type your answer... DUarrow_forwardChemistry Given TETRAPEPTIDE: Prolinyl-Argininyl-Cysteinyl-Tryptophan Predict the direction of the peptide in electrophoresis at pH 7 and pH11.5. (Use table on the upper right for the estimated pK values of some functional groups).arrow_forwardYou may use the following table of pKa values for typical amino acid substituents. alpha carboxylate group Sidechain carboxylate Imidazole alpha amino group Guanidino group First [Select] 2 [Select] 4 Thiol sidechain amino group Consider the following 3 peptides. Last 6 9 12 8 Peptide 1: E-H-A-D-E-K Peptide 2: E-D-R-H-Y-G Peptide 3: G-E-G-D-S-D What would be the order of elution of these peptides for a anion exchange column at pH 7.0? 11 [Select]arrow_forward
- Show the formation of the following peptides A. tyrosyl alanyl glycine B. phenylalanyl tyrosyl seryl histidinearrow_forwardSomatostatin is a tetradecapeptide of the hypothalamus that inhibits the release of pituitary growth hormone. Its amino acid sequence has been determined by a combination of Edman degradations and enzymic hydrolysis experiments. On the basis of the following data, deduce the primary structure of somatostatin: 1. Edman degradation gave PTH-Ala. 2. Selective hydrolysis gave peptides having the following indicated sequences: Phe-Trp Thr-Ser-Cys Lys-Thr-Phe Thr-Phe-Thr-Ser-Cys Asn-Phe-Phe-Trp-Lys Ala-Gly-Cys-Lys-Asn-Phe 3. Somatostatin has a disulfide bridge.arrow_forwardPredict the products P and Q formed when the following peptide is treated with the given reagient. HS. H₂N (b) (c) (d) HS P P OH H₂N. PhNCS DIPEA H₂N. X DH P + Q OH CHarrow_forward
- N-(2-hydroxyethyl)piperazine-N'-(2-ethanesulfonic A purified protein is in a Hepes acid) buffer at pH 7 with 375 mM NaCl. A dialysis membrane tube holds a 2.0 mL sample of the protein solution. The sample tube floats in a beaker containing 1.00 L of the same Hepes buffer, but with 0 mM NaCl, for dialysis. Small molecules and ions (such as Na+, Cl, and Hepes) can to diffuse across the dialysis membrane, but the protein cannot. Assume there are no sample volume changes during the dialysis. Calculate the final concentration of NaCl in the protein sample once the dialysis has come to equilibrium. Calculate the final NaCl concentration in the 2.0 mL protein sample after dialysis in 150 mL of the same Hepes buffer, with 0 mM NaCl, twice in succession. [NaC1] after a single dialysis: [NaCl] after a double dialysis: x10' TOOLS mM mMarrow_forward6arrow_forward13. Explain why the dansyl chloride treatment of a single polypeptide chain followed by its complete acid hydrolysis yields several dansylated amino acids.arrow_forward
