Dna-Binding Compounds. IV. Synthesis and Solution Conformation of a Novel Macrocyle Formed by Coupling of the Side-Chains of Adjacent L-Lysine Residues

1991 ◽  
Vol 44 (11) ◽  
pp. 1649 ◽  
Author(s):  
AM Bray ◽  
DP Kelly ◽  
TK Lim
Keyword(s):  
Carboxylic Acid ◽  
Dimethyl Sulfoxide ◽  
The Novel ◽  
Two Dimensional ◽  
Amino Groups ◽  
Solution Conformation ◽  
Mild Conditions ◽  
Dimethyl Sulfoxide Solution ◽  
Acid Methyl ◽  
Lysine Residues

The novel macrocyclic dilysine derivatives (8S,11S)-11-t-butoxycarbonylamino-2,10-dioxo-1,3,9-triazacyclopentadecane-8-carboxylic acid methyl (5) and t-butyl (6) esters were prepared by coupling of the є-amino groups of adjacent lysine residues of the esters of Boc-Lys-Lys-OR with 1,1′-carbonyldiimidazole under mild conditions. The conformation of (6) in dimethyl sulfoxide solution was determined by the use of a variety of one- and two-dimensional n.m.r. techniques.

scholarly journals The reaction of protein amino groups with methyl 5-iodopyridine-2-carboximidate. A possible general method of preparing isomorphous heavy-atom derivatives of proteins

1973 ◽  
Vol 131 (4) ◽  
pp. 625-635 ◽  
Author(s):  
Malcolm Riley ◽  
Richard N. Perham
Keyword(s):  
Heavy Atom ◽  
Performic Acid ◽  
Amino Groups ◽  
Model Compounds ◽  
Heavy Atoms ◽  
Mild Conditions ◽  
Tryptic Cleavage ◽  
Lysine Residues ◽  
Derivatives Of ◽  
General Method

1. The synthesis of methyl 5-iodopyridine-2-carboximidate and its reaction with amino groups of model compounds and performic acid-oxidized insulin are described. The reagent was designed to introduce heavy atoms into specific sites in proteins. 2. Specific reaction with the amino groups of oxidized insulin can be achieved under reasonably mild conditions giving rise to the corresponding N-monosubstituted amidines. 3. The extent of reaction of this reagent with protein amino groups can be readily determined by difference spectroscopy. Modification of lysine residues inhibits tryptic cleavage at such residues, and this can be of assistance in establishing the site of modification in the primary structure. 4. Evidence is presented to show that methyl 5-iodopyridine-2-carboximidate can react specifically, at pH5.0, with the aromatic amino group of 3-amino-l-tyrosine; the final product of this reaction is a 2-arylbenzoxazole. 5. The use of this reagent as a general method for preparing heavy-atom isomorphous derivatives of proteins is discussed.

The Action of Thrombin on Modified Fibrinogen

1983 ◽  
Vol 49 (03) ◽  
pp. 208-213
Author(s):  
A J Osbahr
Keyword(s):  
Physical Properties ◽  
Negative Charge ◽  
Lysine Residue ◽  
Fibrinopeptide A ◽  
Amino Groups ◽  
Lysine Residues ◽  
Citraconic Anhydride

SummaryThe modification of canine fibrinogen with citraconic anhydride modified the ε-amino groups of the fibrinogen and at the same time generated additional negative charges into the protein. The addition of thrombin to the modified fibrinogen did not induce polymerization; however, the fibrinopeptide was released at a faster rate than from the unmodified fibrinogen. The physical properties of the citraconylated fibrinogen were markedly altered by the modification of 50-60 lysine residues in one hour. A modified fibrinopeptide-A was released by thrombin from the modified fibrinogen and was electrophoretically more anionic than the unmodified fibrinopeptide-A. Edman analysis confirmed the modification of the lysine residue present in the peptide. The rate of removal of citraconylated fibrinopeptide-A from modified fibrinogen by thrombin was 30 to 40 percent greater than the cleavage of unmodified fibrinopeptide-A from unmodified fibrinogen. However, the modification of 60 or more lysine residues in the fibrinogen produced a decrease in the rate of cleavage of citraconylated fibrinopeptide-A. The results suggest that additional negative charge in the vicinity of the attachment of fibrinopeptide-A to canine fibrinogen aids in the removal of the peptide by thrombin.

Aliphatic Carboxylic Acid as Hydrogen-Bond Donor for Converting CO2 and Epoxide into Cyclic Carbonate under Mild Conditions

2021 ◽  
Author(s):  
Zheng Wang ◽  
Yajun Wang ◽  
Qianjie Xie ◽  
Zhiying Fan ◽  
Yehua Shen
Keyword(s):  
Hydrogen Bond ◽  
Carboxylic Acid ◽  
Value Added ◽  
Cyclic Carbonate ◽  
Hydrogen Bond Donor ◽  
Title Reaction ◽  
Aliphatic Carboxylic Acid ◽  
Mild Conditions ◽  
Atmospheric Carbon

The coupling of CO2 and epoxide is promising way to reduce atmospheric carbon by converting it into value-added cyclic carbonate. Pursuing efficient catalysts is highly attractive for the title reaction....

scholarly journals Lysyl oxidase activity and elastin/glycosaminoglycan interactions in growing chick and rat aortas.

1987 ◽  
Vol 105 (3) ◽  
pp. 1463-1469 ◽  
Author(s):  
C Fornieri ◽  
M Baccarani-Contri ◽  
D Quaglino ◽  
I Pasquali-Ronchetti
Keyword(s):  
Hydrophobic Interactions ◽  
Isonicotinic Acid ◽  
Lysyl Oxidase ◽  
Acid Hydrazide ◽  
Elastic Fibers ◽  
Amino Groups ◽  
Lysine Residues ◽  
Oxidase Inhibition

Hydrophobic tropoelastin molecules aggregate in vitro in physiological conditions and form fibers very similar to natural ones (Bressan, G. M., I. Pasquali Ronchetti, C. Fornieri, F. Mattioli, I. Castellani, and D. Volpin, 1986, J. Ultrastruct. Molec. Struct. Res., 94:209-216). Similar hydrophobic interactions might be operative in in vivo fibrogenesis. Data are presented suggesting that matrix glycosaminoglycans (GAGs) prevent spontaneous tropoelastin aggregation in vivo, at least up to the deamination of lysine residues on tropoelastin by matrix lysyl oxidase. Lysyl oxidase inhibitors beta-aminopropionitrile, aminoacetonitrile, semicarbazide, and isonicotinic acid hydrazide were given to newborn chicks, to chick embryos, and to newborn rats, and the ultrastructural alterations of the aortic elastic fibers were analyzed and compared with the extent of the enzyme inhibition. When inhibition was greater than 65% all chemicals induced alterations of elastic fibers in the form of lateral aggregates of elastin, which were always permeated by cytochemically and immunologically recognizable GAGs. The number and size of the abnormal elastin/GAGs aggregates were proportional to the extent of lysyl oxidase inhibition. The phenomenon was independent of the animal species. All data suggest that, upon inhibition of lysyl oxidase, matrix GAGs remain among elastin molecules during fibrogenesis by binding to positively charged amino groups on elastin. Newly synthesized and secreted tropoelastin has the highest number of free epsilon amino groups, and, therefore, the highest capability of binding to GAGs. These polyanions, by virtue of their great hydration and dispersing power, could prevent random spontaneous aggregation of hydrophobic tropoelastin in the extracellular space.

Oxidation of 2-methylpyrroles with perchlorinated iron(III) metalloporphyrin catalysts: a versatile synthesis of symmetric and asymmetric dipyrromethanes

1998 ◽  
Vol 76 (10) ◽  
pp. 1467-1473 ◽  
Author(s):  
Veranja Karunaratne ◽  
David Dolphin
Keyword(s):  
Catalytic Oxidation ◽  
Allylic Alcohols ◽  
The Novel ◽  
Efficient Synthesis ◽  
Mild Conditions ◽  
Metalloporphyrin Catalysts

A variety of substituted 2-methylpyrroles (3-8) were oxidized using the metalloporphyrin catalysts iron(III) meso-tetra(2,6-dichloro-3-sulphonatophenyl)-β-octachloroporphyrin chloride 1 and iron(III) meso-tetra(2,6-dichlorophenyl)-β-octachloroporphyrin chloride 2 under very mild conditions. Treatment of the resulting allylic alcohols 3a-8a with α-free pyrroles 9 and 10 resulted in a very efficient synthesis of the corresponding dipyrromethanes 3b-8b and 3c-8c. Furthermore, the above allylic alcohols when treated with furfurylamine produced the novel (2-furylmethyl)-2-pyrrolylmethylamines 3d-8d.Key words: catalytic oxidation, metalloporphyrins, pyrroles, dipyrromethanes, polyhalogenated porphyrins.

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