Dnp group

The DNP derivative, prepared from 2,4-dinitrofluorobenzene is released from the nitrogen with an anionic ion exchange resin." When used for histidine protection, the DNP group has been observed to migrate to nearby [ysine residues during Fmoc cleavage. ... 

The same set of measurements for DNP-Leu as selectand and 0-9-allylcarbamoyl-10,11-dihydroquinidine as selector displayed a considerably different picture. While no indication for H-bond formation between the aromatic a-amino group and the carbamate of the selector could be deduced, the IR spectra of free and respective complexed forms suggested the occurrence of K-K-interactions of the DNP group as evidenced by a shifted C=C stretching vibration from 1594 to 1588 cm in the stronger bound 5-complex (force constant weakened due to delocalized electrons). This type of shift was not found in the weak TJ-complex, but in the corresponding 5-complex of DNP-N-methyl-Leu as well. The spectral data nicely reflect the binding relationships in HPLC where both DNP-Leu and DNP-N-methyl-Leu are well separated with comparable separation factors, but with an elution order that is opposite compared to DNB-Leu. 

The ACE technique has also been used to determine the two dissociation constants of the complex between anti-lV-dinitrophenyl (DNP) rat monoclonal IgG2b antibody and charged ligands that contained a DNP group by analyzing the change in the electrophoretic mobility of the antibody (Fig. 

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

This experiment indicates that there must be two N-terminal amino acids because two amino acids were labeled with the DNP group. Therefore, there must be two polypeptide chains, connected by disulfide linkages. One has glycine as its N-terminus and the other has phenylalanine. 

This experiment shows that Phe must be the N-terminal amino acid of peptide B because it is labeled with the DNP group. Front hydrolysis of component 1, Val must be attached to Phe from hydrolysis of component 2, Asp must be attached to Val and from hydrolysis of component 3, Glu must be attached to Asp. The sequence of the first four amino acids of peptide B, starting from the N-terminus, is Phe-Val-Asp-Glu. 

Steuerle and HUle (1959) and Hille (1960) developed a method for the quantitative determination of the N-terminal residues normally present in wool. After treatment with l-fluoro-2,4-dinitrobenzene the wool is hydrolyzed and the ether-soluble DNP derivatives applied to a column of nylon 66 powder and developed with phosphate buffer at 60°C. The DNP derivatives of aspartic acid, glutamic acid, serine, threonine, glycine, alanine, and valine separate cleanly and can be readily determined in the eluates. Hence, it is well suited to the determination of N-terminal residues in normal animal fibers. In its present form, however, it is not suitable for general use with proteins or modified wool fibers as some DNP derivatives, such as those incorporating two DNP groups, are bound so strongly by the nylon that they cannot be eluted. 

C>-(2,4-Dinitrophenyl)tyrosineP l is a very acid-stable derivative and therefore fully compatible with the Boc strategy in SPPS. 2,4-Dinitrophenyl (2,4-Dnp) protection is also very resistant toward anhydrous HF, and can be selectively removed by thiolysis prior to or following the final deprotection/resin-cleavage step, making this type of protection useful for further modifications of the tyrosine residue. The thiolysis can be monitored spectro-photometrically, e.g. for 5-Dnp-P-ME at 341 nm (e -12500 M cm ). The Dnp group is also... 

Alternatively, the Dnp group can be introduced in good yield by the reaction of l-fluoro-2,4-dinitrobenzene with Boc-Tyr-OH or Lmoc-iyr-OH in CHjCb in the presence of TEA.P l... 

Suspend the peptide-resin in a round-bottomed flask in the minimum amount of DMF necessary to slurry the resin (ca. 5 mL per gram of resin) and add benzenethiol (20 equiv, 0.102 mL mmol" ) per equivalent of His(Dnp) groups. Stir at rt for 1 h. Filter the resin and wash it thoroughly with DMF, H2O, EtOH, and CH2Q2. Dry thoroughly. It is not practical to remove all the intensely yellow Dnp-benzenethiol product from the resin, and this material will color the crude peptide. It is easily removed during purification of the peptide. ... 

The amino group of the N-terminal amino acid displaces fluoride from l-fluoro-2,4-dinitrobenzene and gives a peptide in which the N-terminal nitrogen is labeled with a 2,4-dinitrophenyl (DNP) group. This is shown for the case of Val-Phe-Gly-Ala in Figure 25.7. The 2,4-dinitrophenyl-labeled peptide DNP-Val-Phe-Gly-Ala is isolated and subjected to hydrolysis, after which the 2,4-dinitrophenyl derivative of the N-terminal amino acid is isolated and identified as DNP-Val by comparing its chromatographic behavior with that of standard samples of 2,4-dinitrophenyl-labeled amino acids. None... 

The mouse IgA myeloma 315, which has antibodylike activity for the 2,4-dinitrophenyl (DNP) group, on treatment with pepsin at pH 3.8... 

Dinitrophenylation of the imidazole NH practically eliminates its basic character, yet the 2,4-dinitrophenyl (DNP) group also shares a less desirable property with real acyl groups it can migrate to free amines ... 

Fig. 14. Comparison of the immune response in rabbits against DNP hapten carried either by notein (O — bovine serum albumin (BSA), containing 18.5 mol of DNP groups/mol BSA) or thetic flexible polymer (A — PHEA vrith 17.3 mol- % of side chains fonned by N-hcxamethylene-2,4-dinitro-aniline, X-PHEA mth 2.9 mol- of this si diain). The immune response is expressed as the titer of the anti-DNP-antibodies circulating in the serum of rabbits aflm llie second immunisation dose. (From Ref. together with unpublished results rf autois)...

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