- Superactivity of MOF-808 toward Peptide Bond Hydrolysis
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MOF-808, a Zr(IV)-based metal-organic framework, has been proven to be a very effective heterogeneous catalyst for the hydrolysis of the peptide bond in a wide range of peptides and in hen egg white lysozyme protein. The kinetic experiments with a series of Gly-X dipeptides with varying nature of amino acid side chain have shown that MOF-808 exhibits selectivity depending on the size and chemical nature of the X side chain. Dipeptides with smaller or hydrophilic residues were hydrolyzed faster than those with bulky and hydrophobic residues that lack electron rich functionalities which could engage in favorable intermolecular interactions with the btc linkers. Detailed kinetic studies performed by 1H NMR spectroscopy revealed that the rate of glycylglycine (Gly-Gly) hydrolysis at pD 7.4 and 60 °C was 2.69 × 10-4 s-1 (t1/2 = 0.72 h), which is more than 4 orders of magnitude faster compared to the uncatalyzed reaction. Importantly, MOF-808 can be recycled several times without significantly compromising the catalytic activity. A detailed quantum-chemical study combined with experimental data allowed to unravel the role of the {Zr6O8} core of MOF-808 in accelerating Gly-Gly hydrolysis. A mechanism for the hydrolysis of Gly-Gly by MOF-808 is proposed in which Gly-Gly binds to two Zr(IV) centers of the {Zr6O8} core via the oxygen atom of the amide group and the N-terminus. The activity of MOF-808 was also demonstrated toward the hydrolysis of hen egg white lysozyme, a protein consisting of 129 amino acids. Selective fragmentation of the protein was observed with 55% yield after 25 h under physiological pH.
- Ly, Hong Giang T.,Fu, Guangxia,Kondinski, Aleksandar,Bueken, Bart,De Vos, Dirk,Parac-Vogt, Tatjana N.
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p. 6325 - 6335
(2018/05/14)
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- DPP-4 inhibitor
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A DPP-4 inhibitor comprising a peptide represented by the formula (1): Xe-Pro/Ala/Hyp-Xa-Xb-Xc-Xd (SEQ ID NO: 16) (wherein Xe is an amino acid residue with an isoelectric point of 5.9 to 6.3; Pro/Ala/Hyp represents Pro, Ala, or Hyp; Xa is an amino acid residue other than Hyp, Pro, and Arg, or deletion; 5 Xb is Gly, Pro, or deletion; Xc is Pro, Ala, or deletion; and Xd is an amino acid residue or deletion) as an active component. The inhibitor can be expected to bring out an effect of lowering blood glucose levels by enhancing effects of incretins; and the inhibitor may be used as a therapeutic agent for diabetes and, in addition, can act on the immune system or the like to be thus used in 10 treatment for skin diseases or the like.
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Page/Page column 11-12
(2016/06/06)
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- Coupling-Reagent-Free Synthesis of Dipeptides and Tripeptides Using Amino Acid Ionic Liquids
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A general method for the synthesis of dipeptides has been developed, which does not require any coupling reagents. This method is based on the reaction of readily available HCl salts of amino acid methyl esters with tetrabutylphosphonium amino acid ionic liquids. The isolation procedure of stepwise treatment with AcOH is easy to carry out. The method was extended to the synthesis of tripeptide, tyrosyl-glycyl-glycine, present in IMREG-1, also.
- Furukawa, Shinya,Fukuyama, Takahide,Matsui, Akihiro,Kuratsu, Mai,Nakaya, Ryotaro,Ineyama, Takashi,Ueda, Hiroshi,Ryu, Ilhyong
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supporting information
p. 11980 - 11983
(2015/08/18)
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- Cell adhesion and extracellular matrix proteins
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Various embodiments of the invention provide human cell adhesion and extracellular matrix proteins (CADECM) and polynucleotides which identify and encode CADECM. Embodiments of the invention also provide expression vectors, host cells, antibodies, agonists, and antagonists. Other embodiments provide methods for diagnosing, treating, or preventing disorders associated with aberrant expression of CADECM.
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- Direct asymmetric intermolecular aldol reactions catalyzed by amino acids and small peptides
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In nature there are at least nineteen different acyclic amino acids that act as the building blocks of poly-peptides and proteins with different functions. Here we report that α-amino acids, β-amino acids, and chiral amines containing primary amine functions catalyze direct asymmetric intermolecular aldol reactions with high enantio-selectivities. Moreover, the amino acids can be combined into highly modular natural and unusual small peptides that also catalyze direct asymmetric intermolecular aldol reactions with high stereoselectivities, to furnish the corre sponding aldol products with up to > 99% ee. Simple amino acids and small peptides can thus catalyze asymmetric aldol reactions with stereoselectivities matching those of natural enzymes that have evolved over billions of years. A small amount of water accelerates the asymmetric aldol reactions catalyzed by amino acids and small peptides, and also increases their stereoselectivities. Notably, small peptides and amino acid tetrazoles were able to catalyze direct asymmetric aldol reactions with high enantioselectivities in water, while the parent amino acids, in stark contrast, furnished nearly racemic products. These results suggest that the prebiotic oligomerization of amino acids to peptides may plausibly have been a link in the evolution of the homochirality of sugars. The mechanism and stereochemistry of the reactions are also discussed.
- Cordova, Armando,Zou, Weibiao,Dziedzic, Pawel,Ibrahem, Ismail,Reyes, Efraim,Xu, Yongmei
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p. 5383 - 5397
(2008/02/13)
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- Zur Totalsynthese von Human-Sekretin
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The synthesis of the heptacosapeptide amide with the primary structure of Human-secretin is described.For this purpose 7 fragments were designed, i.e.H-Gly-Leu-Val-NH2 , Z-Arg(Z2)-Leu-Leu-Gln-OH , Z-Arg(Z2)-Leu-Gln-OH , Z-Arg(Z2)-Glu(OtBu)-Gly-Ala-OH , Z-Arg(Z2)-Leu-OH , Z-Thr(tBu)-Ser(tBu)-Glu(OtBu)-Leu-Ser(tBu)-OH , Adoc-His(Adoc)-Ser(tBu)-Asp(OtBu)-Gly-Thr(tBu)-Phe-OH ; these fragments were consequently assembled to the overall protected total sequence using the Wuensch/Weygand-method with dicyclohexylcarbodiimide.After deprotection by exposure to trifluoroacetic acid in presence of 1,2-ethanediol and water as scavenger, the islated crude product was purified by column chromatography on CM-Sepharose, fast flow.This synthesized Human-secretin showed the full biological activity in comparison to Porcine-secretin. Key words: Gastrointestinal hormone; Human-secretin: synthetic peptide factors.
- Wuensch, E.,Wendlberger, G.,Goehring, W.,Huebener, G.,Traving, B.
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p. 577 - 586
(2007/10/02)
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- Disulfide bridged cyclic peptides containing a cgridri sequence useful in control of hypertension
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Disulfide bridged cyclic peptides are described which are preferably 13 to 20 amino acid residues in length and which include the endocyclic sequence cys-gly-arg-ile-asp-arg-ile. Peptides of this class are selective for and show picomolar-range affinity for the non-guanyl cyclase-coupled atrial peptide receptor. Affinity for this receptor is associated with potentiation of the mean arterial pressure response to atrial peptide and these peptides are therefore useful in control of hypertension. Peptides of most interest are of the formula wherein X1 is the peptidic fragment ser-ser; wherein X2 is a peptidic fragment selected from gly-ser-gly-leu, gly-ala-gly-leu and gly-leu; wherein X3 is the peptidic fragment asn-ser-phe-arg; wherein m is zero or one, n is one and r is one; and wherein A represents an amino terminus or its pharmaceutically--acceptable salt, and B represents a carboxyl terminus or its pharmaceutically-acceptable ester, amide or salt.
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- First-Order Rate Constans for the Racemization of Each Component in a Mixture of Isomeric Dipeptides and their Diketopiperazines
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L-Alanylglycine (L-Ala-Gly), glycyl-L-alanine (Gly-L-Ala), and c-L-Ala-Gly were racemized at 120 deg C in aqueous phosphate-buffered solutions at pH 8.0, a pH value near maximum racemization.The kinetics were followed by regression analysis.The racemization of Ala-Gly and Gly-Ala closelly followed reversible first-order kinetics.The initial rate of racemisation of DKP was fast but soon slowed, likely because of hydrolysis to the dipeptides.The resulting rate was similar to that of the dipeptides.The observed racemization rate constans of the dipeptides and DKP were shown to be independent of the concentration of the peptides and the concetration of buffer.Component isolation studies using preparative TLC and chiral-phase GC analysis, coupled with computer analysis, showed an equilibrium existing between Ala-Gly, Gly-Ala, and DKP and the individual rates of racemization.At equilibrium, the mole fractions are as follows: Ala-Gly, 0.57; DKP, 0.22; Gly-Ala, 0.21.The rate constant for racemization of DKP was only 2 times that of Gly-Ala and 7 times the rate of Ala-Gly.Ala-Gly racemized 20 times and Gly-Ala 66 times faster than free alanine.The results support the influence of neighboring groups in the racemization of dipeptides.Factors that contribute to the rapid racemization (epimerization) are discussed.
- Smith, Grant Gill,Baum, Rocky
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p. 2248 - 2255
(2007/10/02)
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- Relative Partial Molar Enthalpies and Apparent Molar Volumes of Dipeptides in Aqueous Solution
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Enthalpies of dilution at 25 deg C of aqueous solutions of the dipeptides glycylglycine, glycylalanine and alanylalanine have been determined and used to calculate the partial molar enthalpies of the solvent water in the solutions.The partial molar volumes of these dipeptides are also reported.The results are discussed in terms of the likely solute-solvent interactions.
- Dyke, Shaun H.,Hedwig, Gavin R.,Watson, Ian D.
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p. 321 - 332
(2007/10/02)
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- PREPARATIVE ISOLATION AND PROPERTIES OF DIASTEREOMERIC COPPER(II) CHELATES OF SCHIFF BASES OF DIPEPTIDES WITH (α-(N,N-DIMETHYLAMINO)ALKYL)FORMYLCYMANTRENES
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The effect of the planar and central chirality of 1,2-(α-(N,N-dimethylamino)alkyl)formylcymantrene on the chromatographic properties of diastereomeric chelates of Cu2+ with Schiff bases from dipeptides and the aminoalkylformylcymantrenes, 1-(N,
- Tsiryapkin, V. A.,Loim, N. M.,Nedospasova, L. V.,Parnes, Z. N.,Belikov, V. M.,Kursanov, D. N.
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