Dipeptide Synthesis Lab Report
Junnel Metrillo Date Performed: October 27, 2014
2L Group 1 Date Submitted: November 3, 2014
Exercise 6
Dipeptide Sequence Determination
To understand the chemical, structural and functional properties of a certain protein, it is important to determine its amino acid components and sequence. The differences in the composition and sequence of amino acids dictate the differences in structure and function of the proteins and peptides. All amino acids consist of an amino group, a carboxylate group, and an R group. And it varies from one another in the identity of the R group. In this experiment, dipeptide sample …show more content…
1. Paper chromatogram of dipeptide 1 and dipeptide 2 Based on paper chromatogram and Rf values, we can conclude that the amino acid components of the dipeptide 1 sample are Glycine and Leucine (not in sequence) while for dipeptide 2 sample are Alanine and Phenylalanine (not in sequence). We compare the Rf values obtained from unknown and compare it with the standards. The amino acid identity is the one that has the lowest absolute value of difference with the unknown. In using the thin layer chromatography in the experiment, Sanger’s method was also incorporated to determine the proper sequence of the dipeptide. It is a colorimetric method that uses 1- fluoro- 2,4- dinitrobenzene (FDNB) and reacts with free amino , imidazole and phenolic groups forming DNP derivatives. DNP derivatives then have been hydrolyzed to cleave the dipeptide followed by ether extraction. First extraction of ether was used to remove excess ethanol and excess FDNB and leaves an aqueous suspension of the DNP- dipeptide. While in second extraction of ether, the ether phase was the one recovered because it contains the DNP- amino acid and this is governed by the principle “like dissolves like”. DNP- amino acid was run in thin layer chromatography with the standards and obtain the Rf values to get its identity. The DNP- amino acid appeared bright yellow in the chromatogram paper. Visualizing agents used in TLC includes bromocresol green for carboxylic acids, fluorescamine for primary amines, iodine
2L Group 1 Date Submitted: November 3, 2014
Exercise 6
Dipeptide Sequence Determination
To understand the chemical, structural and functional properties of a certain protein, it is important to determine its amino acid components and sequence. The differences in the composition and sequence of amino acids dictate the differences in structure and function of the proteins and peptides. All amino acids consist of an amino group, a carboxylate group, and an R group. And it varies from one another in the identity of the R group. In this experiment, dipeptide sample …show more content…
1. Paper chromatogram of dipeptide 1 and dipeptide 2 Based on paper chromatogram and Rf values, we can conclude that the amino acid components of the dipeptide 1 sample are Glycine and Leucine (not in sequence) while for dipeptide 2 sample are Alanine and Phenylalanine (not in sequence). We compare the Rf values obtained from unknown and compare it with the standards. The amino acid identity is the one that has the lowest absolute value of difference with the unknown. In using the thin layer chromatography in the experiment, Sanger’s method was also incorporated to determine the proper sequence of the dipeptide. It is a colorimetric method that uses 1- fluoro- 2,4- dinitrobenzene (FDNB) and reacts with free amino , imidazole and phenolic groups forming DNP derivatives. DNP derivatives then have been hydrolyzed to cleave the dipeptide followed by ether extraction. First extraction of ether was used to remove excess ethanol and excess FDNB and leaves an aqueous suspension of the DNP- dipeptide. While in second extraction of ether, the ether phase was the one recovered because it contains the DNP- amino acid and this is governed by the principle “like dissolves like”. DNP- amino acid was run in thin layer chromatography with the standards and obtain the Rf values to get its identity. The DNP- amino acid appeared bright yellow in the chromatogram paper. Visualizing agents used in TLC includes bromocresol green for carboxylic acids, fluorescamine for primary amines, iodine