Conformational Flexibility Controls Proton Transfer between the Methionine Hydroxy Sulfuranyl Radical and the N-Terminal Amino Group in Thr−(X)n−Met Peptides

2001 ◽  
Vol 105 (6) ◽  
pp. 1250-1259 ◽  
Author(s):  
Dariusz Pogocki ◽  
Elena Ghezzo-Schöneich ◽  
Christian Schöneich
Keyword(s):  
Proton Transfer ◽  
Conformational Flexibility ◽  
Amino Group ◽  
Terminal Amino

Reaction of metallic nitrilotriacetates with histamine

1969 ◽  
Vol 47 (8) ◽  
pp. 1269-1273 ◽  
Author(s):  
A. L. Beauchamp ◽  
J. Israeli ◽  
H. Saulnier
Keyword(s):  
Potentiometric Titration ◽  
Formation Constants ◽  
Amino Group ◽  
Mixed Complex ◽  
Ph Values ◽  
Titration Curves ◽  
Terminal Amino ◽  
Complex Ion

Cu(II), Ni(II), Co(II), and Zn(II) nitrilotriacetates (MeX−) react with histamine nitrate (LH+) to form a protonated mixed complex MeXLH where the metal appears to be bound only to the tertiary imidazolic nitrogen of histaminium ion. At higher pH values the proton dissociates to yield a mixed complex ion MeXL− in which both the imidazolic nitrogen and the terminal amino group are coordinated. The formation constants of these species were calculated from the potentiometric titration curves.

Synthesis of three Salmonella epitopes for biosensor studies of carbohydrate–antibody interactions

2002 ◽  
Vol 80 (8) ◽  
pp. 1131-1140 ◽  
Author(s):  
Henry N Yu ◽  
Chang-Chun Ling ◽  
David R Bundle
Keyword(s):  
Key Words ◽  
Self Assembled Monolayers ◽  
Antigenic Determinants ◽  
Amino Group ◽  
Assembled Monolayers ◽  
Construction Of Self ◽  
Terminal Amino ◽  
Salmonella Serotypes ◽  
O Antigens ◽  
Antibody Interactions

Disaccharides 1-3 corresponding to the antigenic determinants of Salmonella serotypes A, B, and D1 were synthesized in a form suited for use in biosensors. The disaccharide determinants each contain a unique 3,6-dideoxyhexose, namely abequose (3,6-dideoxy-D-xylo-hexose), paratose (3,6-dideoxy-D-ribohexose), and tyvelose (3,6-dideoxy-D-arabino-hexose), are α-linked to the 3-position of D-mannopyranose. The disaccharides were further derivatized with a linear aglycon that has a terminal amino group, and can be readily coupled to pertinent chains carrying a terminal thiol for the construction of self-assembled monolayers (SAMs). Efficient routes that employed a single 3,6-dideoxygenation step were developed for the synthesis of paratoside 15 and tyveloside 22.Key words: Salmonella O-antigens, lipopolysaccharide, abequose, paratose, tyvelose, 3,6-dideoxyhexose, deoxygenation, glycoside tethers, immobilization via pentenyl glycosides.

scholarly journals New Histamine-Related Five-Membered N-Heterocycle Derivatives as Carbonic Anhydrase I Activators

Molecules ◽  
2022 ◽  
Vol 27 (2) ◽  
pp. 545
Author(s):  
Niccolò Chiaramonte ◽  
Alessio Gabellini ◽  
Andrea Angeli ◽  
Gianluca Bartolucci ◽  
Laura Braconi ◽  
...  
Keyword(s):  
Carbonic Anhydrase ◽  
Imidazole Ring ◽  
Aliphatic Chain ◽  
Amino Group ◽  
Carbonic Anhydrase I ◽  
Terminal Amino ◽  
Human Carbonic Anhydrase ◽  
New Compounds ◽  
Related Compounds ◽  
Micromolar Range

A series of histamine (HST)-related compounds were synthesized and tested for their activating properties on five physiologically relevant human Carbonic Anhydrase (hCA) isoforms (I, II, Va, VII and XIII). The imidazole ring of HST was replaced with different 5-membered heterocycles and the length of the aliphatic chain was varied. For the most interesting compounds some modifications on the terminal amino group were also performed. The most sensitive isoform to activation was hCA I (KA values in the low micromolar range), but surprisingly none of the new compounds displayed activity on hCA II. Some derivatives (1, 3a and 22) displayed an interesting selectivity for activating hCA I over hCA II, Va, VII and XIII.

scholarly journals Analysis of crystalline and solution states of ligand-free spermidine N-acetyltransferase (SpeG) from Escherichia coli

2019 ◽  
Vol 75 (6) ◽  
pp. 545-553 ◽  
Author(s):  
Ekaterina V. Filippova ◽  
Steven Weigand ◽  
Olga Kiryukhina ◽  
Alan J. Wolfe ◽  
Wayne F. Anderson
Keyword(s):  
Escherichia Coli ◽  
Vibrio Cholerae ◽  
Crystal Structures ◽  
Coenzyme A ◽  
Amino Group ◽  
Acetyl Coenzyme A ◽  
E Coli ◽  
Ligand Free ◽  
Acetyl Group ◽  
Terminal Amino

Spermidine N-acetyltransferase (SpeG) transfers an acetyl group from acetyl-coenzyme A to an N-terminal amino group of intracellular spermidine. This acetylation inactivates spermidine, reducing the polyamine toxicity that tends to occur under certain chemical and physical stresses. The structure of the SpeG protein from Vibrio cholerae has been characterized: while the monomer possesses a structural fold similar to those of other Gcn5-related N-acetyltransferase superfamily members, its dodecameric structure remains exceptional. In this paper, structural analyses of SpeG isolated from Escherichia coli are described. Like V. cholerae SpeG, E. coli SpeG forms dodecamers, as revealed by two crystal structures of the ligand-free E. coli SpeG dodecamer determined at 1.75 and 2.9 Å resolution. Although both V. cholerae SpeG and E. coli SpeG can adopt an asymmetric open dodecameric state, solution analysis showed that the oligomeric composition of ligand-free E. coli SpeG differs from that of ligand-free V. cholerae SpeG. Based on these data, it is proposed that the equilibrium balance of SpeG oligomers in the absence of ligands differs from one species to another and thus might be important for SpeG function.

Reaction between Glucose and the Terminal Amino Group of Lysine

Nature ◽  
1951 ◽  
Vol 168 (4278) ◽  
pp. 744-745 ◽  
Author(s):  
R. S. HANNAN ◽  
C. H. LEA
Keyword(s):  
Amino Group ◽  
Terminal Amino

scholarly journals Primaquine derivatives: Modifications of the terminal amino group

2019 ◽  
Vol 182 ◽  
pp. 111640 ◽  
Author(s):  
Branka Zorc ◽  
Ivana Perković ◽  
Kristina Pavić ◽  
Zrinka Rajić ◽  
Maja Beus
Keyword(s):  
Amino Group ◽  
Terminal Amino

scholarly journals Solvent-Free Ring Cleavage Hydrazinolysis of Certain Biginelli Pyrimidines

2018 ◽  
Vol 2018 ◽  
pp. 1-6 ◽  
Author(s):  
Mohamed A. Said ◽  
Wagdy M. Eldehna ◽  
Hazem A. Ghabbour ◽  
Maha M. Kabil ◽  
Nasser S. Al-shakliah ◽  
...  
Keyword(s):  
Hydrazine Hydrate ◽  
Ring Opening ◽  
Solvent Free ◽  
Nucleophilic Attack ◽  
Ring Cleavage ◽  
Amino Group ◽  
Free Ring ◽  
Terminal Amino ◽  
Solvent Free Reaction

Certain Biginelli pyrimidines with ester substitution in C5 were subjected to unexpected ring opening upon solvent-free reaction with hydrazine hydrate to give three products: pyrazole, arylidenehydrazines, and urea/thiourea, respectively. The nonisolable carbohydrazide intermediates are formed firstly followed by the intermolecular nucleophilic attack of terminal amino group of hydrazide function on sp2 C6 rather than the sp3 C4 to give the ring adduct which was produced as a final product.

Amino-terminal groups in zymogen activation: effect of nitrous acid on pepsin

1969 ◽  
Vol 47 (12) ◽  
pp. 1099-1101 ◽  
Author(s):  
T. Hofmann
Keyword(s):  
Nitrous Acid ◽  
Lysine Residue ◽  
Amino Group ◽  
Serine Proteinases ◽  
Zymogen Activation ◽  
Activation Effect ◽  
Amino Terminal ◽  
Tryptophan Residues ◽  
Terminal Amino ◽  
Isoleucine Residue

Nitrous acid rapidly deaminates the N-terminal isoleucine residue of pepsin. The enzyme retains more than 60% of its activity. The loss of 30–40% activity can be ascribed to the reaction of two tryptophan residues with nitrous acid. The single lysine residue is also deaminated. These results are in contrast to those obtained with serine proteinases where nitrous acid causes inactivation due to the deamination of the N-terminal amino group.

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