The reactions of diazonium compounds with amino acids and proteins

Howard, Alma; Wild, Fabian

doi:10.1042/bj0650651

Cited by 117 publications

(49 citation statements)

References 7 publications

(11 reference statements)

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“…32 The high reactivity of these substrates makes them ideal for protein labeling although one of the major drawbacks in using this approach lies in the very poor selectivity often observed in these conjugation reactions. [33][34][35] Diazonium derivatives have been used for non-specific targeting of a number of proteins for a range of applications spanning from the introduction of haptens onto protein conjugates 36 to the supporting of proteins onto PVA polymer matrices. 37 Tryptophan has been reported to react efficiently with diazonium salts such as 3-diazonium-1,2,4-triazole (3-DT) at very low pH (<3) with reactivity decreasing with an increase in pH.…”

Section: Resultsmentioning

confidence: 99%

“…38 All of the other amino acid targets, N-nucleophiles such as Lysine, (poly)peptide N-termini and Arginine, or Cnucleophiles Tyrosine and Histidine, and the S-nucleophiles free Cysteine, present acid/base moieties which affect their reactivity towards diazonium coupling reagents. 33 A general trend for the N-nucleophiles (Lys, Arg and N-terminal amine) is that the lower the pH, the higher proportion of the nucleophilic nitrogen centers will be in their protonated form, which is non-reactive towards electrophilic reagents.Histidine and Tyrosine follow the same trend, 37 albeit for different reasons. Protonation of the His basic nitrogen removes electronic density from its aromatic ring, which can reduce -or even eliminate, depending on the pH -its nucleophilic character.…”

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confidence: 99%

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Direct Peptide Bioconjugation/PEGylation at Tyrosine with Linear and Branched Polymeric Diazonium Salts

et al. 2012

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Direct polymer conjugation at peptide tyrosine residues is described. In this study Tyr residues of both leucine enkephalin and salmon calcitonin (sCT) were targeted using appropriate diazonium salt-terminated linear monomethoxy poly(ethylene glycol)s (mPEGs) and poly(mPEG) methacrylate prepared by atom transfer radical polymerization. Judicious choice of the reaction conditionspH, stoichiometry, and chemical structure of diazonium saltled to a high degree of site-specificity in the conjugation reaction, even in the presence of competitive peptide amino acid targets such as histidine, lysines, and N-terminal amine. In vitro studies showed that conjugation of mPEG2000 to sCT did not affect the peptide’s ability to increase intracellular cAMP induced in T47D human breast cancer cells bearing sCT receptors. Preliminary in vivo investigation showed preserved ability to reduce [Ca2+] plasma levels by mPEG2000-sCT conjugate in rat animal models.

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Section: Resultsmentioning

confidence: 99%

mentioning

confidence: 99%

Direct Peptide Bioconjugation/PEGylation at Tyrosine with Linear and Branched Polymeric Diazonium Salts

et al. 2012

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“…Inhibition of intact cell enzyme activity by "nonpenetrating" reagents represents one experimental (32,33). DBSA has previously been employed to label surface proteins of the human erythrocyte (17) and to demonstrate that adenosine monophosphate was an ectoenzyme of guinea pig PMN (18).…”

Section: Methodsmentioning

confidence: 99%

Evidence that the superoxide-generating system of human leukocytes is associated with the cell surface.

Goldstein¹,

Cerqueira²,

Lind³

et al. 1977

J. Clin. Invest.

227

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A B S T R A C T Superoxide anion (02 *) generation by human peripheral blood polymorphonuclear leukocytes is enhanced when these cells encounter appropriate soluble or particulate stimuli. O2 generation requires intact, viable cells and proceeds independently of phagocytosis. To investigate the possibility that the 02--generating system is associated with the outer surface of the polymorphonuclear leukocyte plasma membrane, we have examined the effects upon 02 production of p-diazobenzenesulfonic acid, a reagent which can react predominantly with proteins of the external cell membrane. When normal human polymorphonuclear leukocytes were preincubated with cytochalasin B (to minimize endocytosis) and then exposed to the surface-active lectin, concanavalin A, the cells were stimulated to generate 02 in a concentration-and time-dependent fashion and selectively to discharge the granule-associated enzyme, lysozyme, into the surrounding medium. These responses, as well as cellular binding of [3H]concanavalin A, could be blocked by a-methyl-D-mannoside. Brief treatment (<5 min at 4°C) of the cells with p-diazobenzenesulfonic acid (1.0-5.0 mM) significantly interfered with concanavalin A-mediated 0°generation but had no influence upon lysozyme release or upon binding of [3H]concanavalin A. The diazonium salt did not alter cell viability or the specific activity of the cytoplasmic enzyme, lactate dehydrogenase (inhibitable under conditions which allowed entry of this reagent into the cytosol). p-Diazobenzenesulfonic acid, therefore, very likely exerted its effects at the cell surface of the intact polymorphonuclear leukocyte, selectively inhibiting 02 production (either directly or indirectly)

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“…This can be accomplished only by first conjugating carrier with DNP, since extensive conjugation with R may occupy too many of the ,-amino groups available for conjugation with DNP (15). When carrying out the reaction in this order it is possible that the I)NP group is modified by azocoupling in the 6-position of the benzene ring.…”

Section: Response To R-dnp-sheep Red Cell Stroma--this Experiments Wamentioning

confidence: 99%

Competition of Hastens

Amkraut

Garvey

Campbell

1966

The Journal of Experimental Medicine

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Groups of rabbits were injected with either bovine serum albumin, sheep red cell stroma, or keyhole limpet hemocyanin to which 2,4-dinitrophenyl and/or p-azophenyl arsonate groups had been coupled. Groups of animals received either doubly coupled antigen or an equivalent mixture of singly coupled antigens. Materials were injected intravenously as a solution or subcutaneously and intramuscularly in complete Freund's adjuvant. The presence of dinitrophenyl groups on the immunizing antigen could suppress, partially or completely, the antibody response to p-azophenyl arsonate when this hapten was located on the same molecule. Suppression was dependent on the ratio of haptenic groups on the molecule, appeared to be greatly affected by the method of immunization, and could be demonstrated in all three antigen systems. Partial suppression was manifested in decreased frequency and delayed appearance of the response as well as decreased maximal antibody titers. These findings appear irreconcilable with the possibility of direct clonal selection of antibody-producing cells by unprocessed antigen.

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The reactions of diazonium compounds with amino acids and proteins

Cited by 117 publications

References 7 publications

Direct Peptide Bioconjugation/PEGylation at Tyrosine with Linear and Branched Polymeric Diazonium Salts

Direct Peptide Bioconjugation/PEGylation at Tyrosine with Linear and Branched Polymeric Diazonium Salts

Evidence that the superoxide-generating system of human leukocytes is associated with the cell surface.

Competition of Hastens

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