Publications (14)18.94 Total impact
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Article: Studies on the synthetic methodology of head to tail cyclization of linear peptides
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ABSTRACT: Our recent studies on the synthetic methodology of head to tail cyclization of linear peptides are summarized in this paper. Ten cyclopeptides including six cyclopentapeptides as candidates of LHRH antagonists, two cyclopentapeptides, and two cycloheptapeptides which were isolated from Chinese medicinal herbs were synthesized using an organic phosphorus reagent, DEPBT, and were selected as model peptides for studying the factors that influence the cyclization yields. Our results show that the coupling reagent choice and linear peptide sequence are the two most important considerations that determine the success or failure for a cyclization reaction. Effects of different metal ions on the cyclization were also studied. The results suggest that Na+ is suitable for promoting the cyclization of linear pentapeptides while bigger Cs+ is better for promotion of the ring closure of linear heptapeptides. Application of Pac ester in thioester method for synthesis of cyclopeptides was studied. N-protected amino acid and peptide thioesters with Pac group were readily purified in each step of synthesis. The Pac group was easy to remove with zinc powder in acetic acid and its flexibility allows elongatation of the peptide chain from either N-or C-terminal.Letters in Peptide Science 04/2012; 10(5):571-579. -
Article: Enzymatic Synthesis of Dipeptide Derivatives Containing Noncoded Amino Acids in Organic Solvents†
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ABSTRACT: A series of dipeptide derivatives containing non-coded amino acids, N-Boc-4-X-Phe-Ala-NHNHPh (X = Cl, Br, I, NO2), were synthesized by using thermoase in organic solvents. The physical data were consistent with the same samples prepared by 3-(diethoxyphosphoryloxy)-1, 2,3-benzotriazin-4 (3H)-one (DEPBT). Influence of different substituted groups of the noncoded amino acids and different organic solvents on the enzymatic peptide synthesis was studied.Chinese Journal of Chemistry 08/2010; 20(11):1354 - 1357. · 0.75 Impact Factor -
Article: Application of DEPBT on the Synthesis of the Protected Dipeptides Containing Histidine with Unprotected Imidazole Group by Solution Method
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ABSTRACT: 3-(Diethoxyphosphoryloxy)-1, 2, 3-benzotriazin-4(3H)-one (DEPBT) was an organophosphorus coupling reagent developed by our group. It was an effective coupling reagent for the synthesis of protected peptides containing Tyr, Ser and Thr with unprotected hydroxy group on their side chain. The further study of the synthesis of a series of protected dipeptides containing histidine with unprotected imidazole group using DEPBT is reported. During the synthetic procedure, the imidazole group of histidine did not need to be protected. When the carboxyl components were N-protected aromatic amino acids or basic amino adds, the yields were relatively high (63%—81%). However, when the carboxyl components were N-protected acidic amino adds, the yields were relatively low (47%—48%). The results expanded the application of DEPBT on the synthesis of bioactive peptides containing histidine.Chinese Journal of Chemistry 08/2010; 21(7):801 - 804. · 0.75 Impact Factor -
Article: Application of Pac Ester in Thioester Method for the Synthesis of Cyclopentapeptides
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ABSTRACT: Thioester method for the synthesis of cyclopeptides is improved by using Pac (Pac = phenacyl, CH2COC6H5) ester as a protecting group of 3-mercaptopropionic acid. The Pac group is easy to be removed from C-terminal with zinc in acetic acid. The protected glycine thioester and peptide thioesters synthesized by the improved method, are easy to be purified, so the final linear peptides are pure enough for the following cyclization. Furthermore, this method is flexible for peptide chain elongation, either from C-terminal or from N-terminal. So it is an efficient and practical method for synthesis of bioactive peptides. Two N-protected pentapeptide thioesters, Boc-Pro-Tyr-Leu-Ala-GlySCH2CH2COOPac and Boc-Ala-Tyr-Leu-Ala-Gly-SCH2CH2-COOPac were synthesized by the improved thioester method. After deprotecting Pac ester with zinc in aqueous acetic acid and Boc group with trifluoroacetic acid in CH2Cl2, two free pentapeptide thioesters were obtained. Ag+-assisted cyclization in acetate buffered solution afforded two cyclic pentapeptides c(Pro-Tyr-Leu-Ala-Gly) and c(Ala-Tyr-Leu-Ala-Gly). Effects of different buffer pH, different Ag+ concentrations, etc. on the cyclization were studied.Chinese Journal of Chemistry 08/2010; 21(7):864 - 870. · 0.75 Impact Factor -
Article: APPLICATION OF DEPBT FOR SYNTHESIS OF N-PROTECTED PEPTIDE ALCOHOLS AND ITS DERIVATIVES
Synthetic Communications 08/2006; 32(3)(473–480 (2002)):473-480. · 1.06 Impact Factor -
Article: DEPBT as an efficient coupling reagent for amide bond formation with remarkable resistance to racemization.
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ABSTRACT: 3-(Diethoxyphosphoryloxy)-1, 2, 3-benzotriazin-4(3H)-one (DEPBT) is an effective coupling reagent for synthesis of linear and cyclic peptides by both solution and solid-phase peptide synthesis. DEPBT mediates amide bond formation with remarkable resistance to racemization. When DEPBT is used as a coupling reagent, it is not necessary to protect the hydroxy group of the amino component (such as tyrosine, serine, and threonine) and the imidazole group in the case of histidine. The high efficiency of DEPBT and its utility have been demonstrated in the syntheses of complex natural products such as ramoplanin A2, ramoplanose aglycon, ustiloxin, and teicoplanin aglycon.Biopolymers 02/2005; 80(2-3):172-8. · 2.87 Impact Factor -
Article: Synthesis of cyclopentapeptides and cycloheptapeptides by DEPBT and the influence of some factors on cyclization.
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ABSTRACT: Three cyclic peptides - cyclo(GlyAlaTyrLeuAla), cyclo(GlyProTyrLeuAla) and cyclo(GlyTyrGlyGlyProPhePro) - isolated and identified from medicinal herbs were chosen as model cyclic peptides to study the influence of the linear precursors and coupling reagents on cyclization. The 17 linear precursors of these three cyclic peptides were synthesized and cyclized using 3-(diethoxyphosphoryloxy)-(1-3)-benzotriazin-4 (3H)-one (DEPBT) as the major coupling reagent. The present work shows that: (i) the effects of linear peptide precursors on the cyclization are complex but some guidelines for choosing suitable precursor for cyclization could be considered; and (ii) DEPBT results in a higher cyclization yield compared with other coupling reagents. In addition, it was confirmed that peptides containing alternating D and L residues favor cyclization.European Journal of Allergy and Clinical Immunology 09/2002; 60(2):95-103. · 1.30 Impact Factor -
Article: Studies on the synthesis of cyclic pentapeptides as LHRH antagonists and the factors that influence cyclization yield.
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ABSTRACT: Six cyclic pentapeptides containing two or three non-protein amino acids have been synthesized by cyclization of linear precursors in dilute solution and characterized by TLC. HPLC, NMR, melting point. specific rotation etc. A total of 72 cyclization reactions were carried out to study the factors that influence head-to-tail cyclization: linear precursor sequence, coupling reagent, residue configuration, the proportion of DMAP additive, concentration, reaction temperature and reaction time. The cyclic pentapeptides will be modified by active moieties and evaluated as LHRH antagonists.Journal of Peptide Science 09/2002; 8(8):418-30. · 1.80 Impact Factor -
Article: Recent progress on immobilization of enzymes on molecular sieves for reactions in organic solvents.
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ABSTRACT: Enzymes exhibit high selectivity and reactivity under normal conditions but are sensitive to denaturation or inactivation by pH and temperature extremes, organic solvents, and detergents. To extend the use of these biocatalysts for practical applications, the technology of immobilization of enzymes on suitable supports was developed. Recently, these immobilized biomolecules have been widely used and a variety of immobilization supports have been studied. The majority of these supports cover diverse kinds of materials such as natural or synthetic polyhydroxylic matrixes, porous inorganic carriers, and all kinds of functional polymers. Microporous molecular sieve, zeolite, has attracted extensive interest in research because of its distinctive physical properties and geochemistry. Recently, with the discovery of a new family of mesoporous molecular sieves, MCM-41, this series of materials shows great potential for various applications. Molecular sieves involve such a series of materials that can discriminate between molecules, particularly on the basis of size. As support materials, they offer interesting properties, such as high surface areas, hydrophobic or hydrophilic behavior, and electrostatic interaction, as well as mechanical and chemical resistance, making them attractive for enzyme immobilization. In this article, different types of molecular sieves used in different immobilization methods including physical adsorption on zeolite, entrapment in mesoporous and macroporous MCM series, as well as chemically covalent binding to functionalized molecular sieves are reviewed. Key factors affecting the application of this biotechnology are discussed systematically, and immobilization mechanisms combined with newly developed techniques to elucidate the interactions between matrixes and enzyme molecules are also introduced.Applied Biochemistry and Biotechnology 06/2002; 101(2):113-29. · 1.94 Impact Factor -
Article: Promotion of cyclization of linear pentapeptides and heptapeptide by different univalent metal ions.
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ABSTRACT: Univalent metal ions such as Na+, K+ and Cs+ can enhance not only the cyclization yields of some linear pentapeptides and heptapeptide but also their cyclization rates while some bivalent and trivalent metal ions such as Mg2+, Ca2+, Zn2+, Fe2+, Ni2+ and Cr3+ elevate neither the cyclization yields nor the cyclization rates and some of them prevent the cyclization.Chemical Communications 04/2002; · 6.17 Impact Factor -
Article: Synthesis of N-protected peptide alcohols catalyzed by subtilisin or alpha-chymotrypsin in organic solvents.
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ABSTRACT: A series of N-protected peptide alcohols were synthesized using amino alcohols with unprotected hydroxy groups as amino components by the catalysis of subtilisin or alpha-chymotrypsin in organic solvents. N-protected aromatic amino acid esters were more suitable as acyl donors for subtilisin. The influences of different N-protecting groups, organic solvents, and content of water on synthesis of N-protected peptide alcohols were systematically studied.Preparative Biochemistry & Biotechnology 03/2002; 32(1):29-37. · 0.47 Impact Factor -
Article: Application of an Organophosphorus Reagent Depbt for Synthesis of Cycloheptapeptide
Synthetic Communications 12/2000; 30(23):4233-4240. · 1.06 Impact Factor -
Article: Enzymatic Peptide Synthesis in Organic Solvent with Different Zeolites as Immobilization Matrixes
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ABSTRACT: A series of zeolite immobilized α-chymotrypsin and thermolysin with microporous Y zeolites (HY, NH4Y, NaY) and mesoporous dealuminized DAY zeolites (HDAY, HNH4DAY) as matrixes have been prepared to catalyze peptide bond formation in organic solvents for the first time. The results indicated that most zeolite immobilized enzymes were active for peptide syntheses in organic media, and still had catalytic activity to some extent after being reused five times. According to the results, the immobilization effect of microporous Y zeolite was better than that of mesoporous DAY zeolite, suggesting that microporous Y zeolite can form more powerful hydrogen bonds with enzyme molecules since there are more hydroxyl groups on the Y zeolite than on the DAY zeolite. In addition, the influences of some reaction conditions such as reaction time and water content of the solvent on the enzymatic peptide synthesis were also studied and optimized. For the two kinds of proteases, NH4Y zeolite did not show its advantages for thermolysin, but was more suitable for α-chymotrypsin as an immobilization matrix.Tetrahedron. -
Article: Enzymatic synthesis and bioactivity of estradiol derivative conjugates with different amino acids
Tetrahedron. 61(24):5933-5941.
Top co-authors
Top Journals
Institutions
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2000–2010
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Peking University
- • Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education
- • Department of Chemistry
Beijing, Beijing Shi, China
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2002
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SickKids
Toronto, Ontario, Canada
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