1946-82-3Relevant articles and documents
Preprogramming Complex Hydrogel Responses using Enzymatic Reaction Networks
Postma, Sjoerd G. J.,Vialshin, Ilia N.,Gerritsen, Casper Y.,Bao, Min,Huck, Wilhelm T. S.
supporting information, p. 1794 - 1798 (2017/02/05)
The creation of adaptive matter is heavily inspired by biological systems. However, it remains challenging to design complex material responses that are governed by reaction networks, which lie at the heart of cellular complexity. The main reason for this slow progress is the lack of a general strategy to integrate reaction networks with materials. Herein we use a systematic approach to preprogram the response of a hydrogel to a trigger, in this case the enzyme trypsin, which activates a reaction network embedded within the hydrogel. A full characterization of all the kinetic rate constants in the system enabled the construction of a computational model, which predicted different hydrogel responses depending on the input concentration of the trigger. The results of the simulation are in good agreement with experimental findings. Our methodology can be used to design new, adaptive materials of which the properties are governed by reaction networks of arbitrary complexity.
Peptide Tyrosinase Activators
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, (2015/06/10)
Peptides that increase melanin synthesis are provided. These peptides include pentapeptides YSSWY, YRSRK, and their variants. The peptides may activate the enzymatic activity of tyrosinase to increase melanin synthesis. The pharmaceutical, cosmetic, and other compositions including the peptides are also provided. The methods of increasing melanin production in epidermis of a subject are provided where the methods include administering compositions comprising an amount of one or more peptides effective to increase the melanin production. The methods also include treating vitiligo or other hypopigmentation disorders with compositions including one or more peptides.
Characteristics of early Maillard reaction products by electrospray ionization mass spectrometry
Li, Chuanjiang,Wang, Hui,Zhang, Yinfeng,Juárez, Manuel,Shao, Guangjie,Ruan, Eric Dongliang
, p. 7452 - 7456 (2015/04/22)
It is crucial to characterize early Maillard reaction products and the important compounds formed in the early stage of Maillard reactionas Amadori rearrangement products are the most important modifications in food science. We report here that using electrospray ionization-mass spectrometry (ESI-MS) to directly characterize fragmentation behaviour of Amadori rearrangement products in a reaction model system using six selected amino acids (arginine, asparagine, glutamine, histidine, lysine and tryptophan) and their N-terminal acetylated forms with two reducing disaccharides, lactose and maltose. The fragmentation behaviour of Amadori rearrangement products was illustrated by Tandem MS (MS2) with collision-induced dissociation (CID). Results showed that the sugar moiety was preferentially fragmented, where by the neutral loss of small molecules, such as 18 Da, 36 Da, 216 Da, 246 Da and 324 Da from disaccharide moieties. Among the fragmented ions, [M-246 + H]+ of disaccharides were relatively stable and they were further studied for fragmentation mechanisms based on representatives of lysine and Nα-Ac-lysine. The study is useful to understand the fundamentals of glycation in complex protein systems based on ESI-MS related techniques.
A fundamental study of amadori rearrangement products in reducing sugar-amino acid model system by electrospray ionization mass spectrometry and computation
Zhang,Ruan,Wang,Ruan,Shao,Aalhus,Juárez
, p. 2941 - 2944 (2014/06/09)
It is crucial to characterize Amadori rearrangement products (ARPs) formed in the early stage of Maillard reaction, one of the most important modifications in food science. We setup a reaction model system using six selected amino acids (arginine, asparagines, glutamine, histamine, lysine and tryptophan) and their N-terminal acetylated forms with different reducing sugars for a fundamental study of Amadori rearrangement products. The effects on forming Amadori rearrangement products were studied by using electrospray ionization mass spectrometry (ESI-MS). The reaction rate was affected by reaction temperature, reaction time, property of sugars and amino acids and the fragmentation mechanism of Amadori rearrangement products was illustrated by tandem MS (MS2) with collision-induced dissociation. The proposed fragmentation mechanism of Amadori rearrangement products in MS2 was provided based on MS2 data and it was supported by their computational data of density functional theory (DFT) at the B3LYP/6-31++G(d,p) level.
The multiple Maillard reactions of ribose and deoxyribose sugars and sugar phosphates
Munanairi, Admire,O'Banion, Steven K.,Gamble, Ryan,Breuer, Elizabeth,Harris, Andrew W.,Sandwick, Roger K.
, p. 2575 - 2592 (2008/03/27)
Ribose 5-phosphate (R5P) undergoes the Maillard reaction with amines at significantly higher rates than most other sugars and sugar phosphates. The presence of an intramolecular phosphate group, which catalyzes the early stages of the Maillard reaction, provides the opportunity for the R5P molecule to undergo novel reaction paths creating unique Maillard products. The initial set of reactions leading to an Amadori product (phosphorylated) and to an α-dicarbonyl phosphate compound follows a typical Maillard reaction sequence, but an observed phosphate hydrolysis accompanying the reaction adds to the complexity of the products formed. The reaction rate for the loss of R5P is partially dependent on the pKa of the amine but also is correlated to the protonation of an early intermediate of the reaction sequence. In the presence of oxygen, a carboxymethyl group conjugated to the amine is a major product of the reaction of R5P with N-acetyllysine while little of this product is generated in the absence of oxygen. Despite lacking a critical hydroxyl group necessary for the Maillard reaction, 2-deoxyribose 5-phosphate (dR5P) still generates an Amadori-like product (with a carbonyl on the C-3 carbon) and undergoes phosphate cleavage. Two highly UV-absorbing products of dR5P were amine derivatives of 5-methylene-2-pyrrolone and 2-formylpyrrole. The reaction of dR5P with certain amines generates a set of products that exhibit an interesting absorbance at 340 nm and a high fluorescence.
Low molecular weight components of cartilage, complexes of metals with amino acids, DI-peptides and analogs thereof; processes for preparation and therapeutic uses thereof
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, (2008/06/13)
Low molecular weight components extracted from shark cartilage and complexes made of copper with amino acid or dipeptide units or analogs thereof are disclosed. Methods are disclosed for the inhibition of angiogenesis (neovascularization) in an animal through the administration of these complexes, which results in treating angiogenesis-dependent diseases.
Molecular rotations of N(α)-acyl-L-lysines at various pH values
Soejima,Akagi,Izumiya
, p. 2618 - 2620 (2007/10/02)
Molecular rotations of N(α)-acyl-L-lysines were determined in water and in water containing various amounts of HCl or NaOH. The acyl groups were formyl, acetyl, propionyl, and butyryl. Each N(α)-acyl-L-lysine exhibited more negative rotation in HCl or NaOH solution than in water. The plot of molecular rotation against amount of HCl or NaOH resembled that of a D-α-amino acid even though N(α)-acyl-lysine was of L-form. The reason for this is discussed from the standpoint of steric factors. N(ε)-Acyl-L-lysines corresponding to the N(α)-acyl-L-lysines were synthesized as reference compounds. It was found that water-soluble N(ε)-acyl-L-lysines can be easily prepared by acylation of the Cu complex solution of L-lysine hydrochloride in the presence of triethylamine. The molecular rotation plots for N(ε)-acyl-L-lysines were typical of L-α-amino acids.
Acetylation under ultrasonic conditions: Convenient preparation of N-acetylamino acids
Veera Reddy,Ravindranath
, p. 257 - 264 (2007/10/02)
An efficient and simple method of preparation of acetylamino acids from amino acids under ultrasonic conditions is described. The reactions proceed without racemization and the yields are almost quantitative.
APPLICATION DE LA RMN A L'ETUDE DES REACTIONS DU FORMALDEHYDE AVEC LES FONCTIONS AMINEES DE L'ALANINE ET DE LA LYSINE EN FONCTION DU pH DU MILIEU
Tome, D.,Naulet, N.,Martin, G. J.
, p. 361 - 366 (2007/10/02)
Reactions of formaldehyde with the amino groups of alanine and lysine have been studied as a function of the pH using carbon and proton NMR.The first addition reaction giving monohydroxymethyl, is equilibrated and the determination of the constants shows a much higher reactivity for the non protonated form of the amino group.The extent of addition is greater with the ε amino group of lysine than with the α amino group.With compounds possessing only one reactive function (alanine, Nα-acetyllysine), the principal derivative is the monohydroxymethyl.With lysine, which has two groups able to react with formaldehyde, the monohydroxymethyls are the only products observed in acidic medium; however, in a pH range of 5 to 10, these hydroxymethyls are able to condense with ech to other to form a dimethylene ether bonding.In each case, the hydroxymethyls can be reduced to monomethyls.The Nε meethyllysine undergoes a new hydroxymethylation which gives the Nε dimethyllysine after reduction.
