DNP peptides

Separated the DNP-peptides from the peptides that did not contain DNP groups. 

Isolated four of the DNP-peptides, which were named B1 through B4. 

Strongly hydrolyzed each DNP-peptide to give free amino acids. 

The iron was removed from the peptide by oxidation with performic acid and the resulting peptide after purification over a column of talcum powder was treated with NBS (Saltiel and Patchornik, 1961) at pH 2, for 20 min at room temperature. Excess NBS was destroyed by the addition of formic acid. The reaction mixture was dinitrophenylated at pH 8.5, and the DNP-peptides were hydrolyzed with HCl. After resolution by two-dimensional paper chromatography DNP-Val, DNP-Thr, and DNP-Thr-Val-Glu were identified. The latter was formed due to incomplete hydrolysis of the peptide bond next to valine. The extent of cleavage of the His-Thr bond was found to be 20 %. 

Peptide Amino acids present Strength of amino acid after hydrolysis of Peptide DNP-Peptide structure... 

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