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Title: Unusual chemical properties of N-terminal histidine residues of glucagon and vasoactive intestinal peptide

Abstract

An N-terminal histidine residue of a protein or peptide has two functional groups, viz., an alpha-amino group and an imidazole group. A new procedure, based on the competitive labeling approach described by Duggleby and Kaplan has been developed by which the chemical reactivity of each functional group in such a residue can be determined as a function of pH. Only very small amounts of material are required, which makes it possible to determine the chemical properties in dilute solution or in proteins and polypeptides that can be obtained in only minute quantities. With this approach, the reactivity of the alpha-amino group of histidylglycine toward 1-fluoro-2,4-dinitrobenzene gave an apparent pK /sub a/ value of 7.64 +/- 0.07 at 37 degrees C, in good agreement with a value of 7.69 +/- 0.02 obtained by acid-base titration. However, the reactivity of the imidazole function gave an apparent pK /sub a/ value of 7.16 +/- 0.07 as compared to the pK /sub a/ value of 5.85 +/- 0.01 obtained by acid-base titration. Similarly, in glucagon and vasoactive intestinal peptide (VIP), apparent pKa values of 7.60 +/- 0.04 and 7.88 +/- 0.18, respectively, were obtained for the alpha-amino of their N-terminal histidine, and pKa valuesmore » of 7.43 +/- 0.09 and 7.59 +/- 0.18 were obtained for the imidazole function.« less

Authors:
; ; ;
Publication Date:
OSTI Identifier:
5023409
Resource Type:
Journal Article
Journal Name:
Biochemistry; (United States)
Additional Journal Information:
Journal Volume: 4
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES; GLUCAGON; AMINO ACID SEQUENCE; PEPTIDES; CARBON 14 COMPOUNDS; HISTIDINE; PH VALUE; SWINE; TRACER TECHNIQUES; TRITIUM; AMINO ACIDS; ANIMALS; AZOLES; BETA DECAY RADIOISOTOPES; BETA-MINUS DECAY RADIOISOTOPES; CARBOXYLIC ACIDS; DOMESTIC ANIMALS; HETEROCYCLIC ACIDS; HETEROCYCLIC COMPOUNDS; HORMONES; HYDROGEN ISOTOPES; IMIDAZOLES; ISOTOPE APPLICATIONS; ISOTOPES; LABELLED COMPOUNDS; LIGHT NUCLEI; MAMMALS; MOLECULAR STRUCTURE; NUCLEI; ODD-EVEN NUCLEI; ORGANIC ACIDS; ORGANIC COMPOUNDS; ORGANIC NITROGEN COMPOUNDS; PEPTIDE HORMONES; POLYPEPTIDES; PROTEINS; RADIOISOTOPES; VERTEBRATES; YEARS LIVING RADIOISOTOPES; 550201* - Biochemistry- Tracer Techniques

Citation Formats

Hefford, M.A., Evans, R.M., Oda, G., and Kaplan, H. Unusual chemical properties of N-terminal histidine residues of glucagon and vasoactive intestinal peptide. United States: N. p., 1985. Web. doi:10.1021/bi00325a009.
Hefford, M.A., Evans, R.M., Oda, G., & Kaplan, H. Unusual chemical properties of N-terminal histidine residues of glucagon and vasoactive intestinal peptide. United States. doi:10.1021/bi00325a009.
Hefford, M.A., Evans, R.M., Oda, G., and Kaplan, H. Tue . "Unusual chemical properties of N-terminal histidine residues of glucagon and vasoactive intestinal peptide". United States. doi:10.1021/bi00325a009.
@article{osti_5023409,
title = {Unusual chemical properties of N-terminal histidine residues of glucagon and vasoactive intestinal peptide},
author = {Hefford, M.A. and Evans, R.M. and Oda, G. and Kaplan, H.},
abstractNote = {An N-terminal histidine residue of a protein or peptide has two functional groups, viz., an alpha-amino group and an imidazole group. A new procedure, based on the competitive labeling approach described by Duggleby and Kaplan has been developed by which the chemical reactivity of each functional group in such a residue can be determined as a function of pH. Only very small amounts of material are required, which makes it possible to determine the chemical properties in dilute solution or in proteins and polypeptides that can be obtained in only minute quantities. With this approach, the reactivity of the alpha-amino group of histidylglycine toward 1-fluoro-2,4-dinitrobenzene gave an apparent pK /sub a/ value of 7.64 +/- 0.07 at 37 degrees C, in good agreement with a value of 7.69 +/- 0.02 obtained by acid-base titration. However, the reactivity of the imidazole function gave an apparent pK /sub a/ value of 7.16 +/- 0.07 as compared to the pK /sub a/ value of 5.85 +/- 0.01 obtained by acid-base titration. Similarly, in glucagon and vasoactive intestinal peptide (VIP), apparent pKa values of 7.60 +/- 0.04 and 7.88 +/- 0.18, respectively, were obtained for the alpha-amino of their N-terminal histidine, and pKa values of 7.43 +/- 0.09 and 7.59 +/- 0.18 were obtained for the imidazole function.},
doi = {10.1021/bi00325a009},
journal = {Biochemistry; (United States)},
number = ,
volume = 4,
place = {United States},
year = {1985},
month = {2}
}