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1.
以N-保护消旋氨基酸为羧基组分的酶促合成肽的研究 总被引:1,自引:0,他引:1
用不同的氨基保护的消旋氨基酸或酯作为羧基组分,在α-胰凝乳蛋白酶或木瓜蛋白酶的催化下与另一氨基酸的酰胺或酯缩合形成预期的光活性肽产物。以L-构型底物计算肽的产率为55%~83%,化合物的物理学常数与用相应的N-保护-L-氨基酸或酯为羧基组分,分别用化学法或酶促法测定所得结果一致。研究结果表明:利用酶的立体专一性,在形成肽键的过程中进行立体选择可得到光学活性的产物而不需预先拆分;只要溶剂体系中含有酶所需要的微量必需水,酶促反应在有机溶剂中可以顺利地进行。 相似文献
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生物活性肽 ,特别是寡肽 ,在免疫调节、激素调节、酶抑制、抗菌、抗病毒等方面有很大的应用潜力[1] .另外 ,调味肽也越来越显示出其在应用上的重要性 .肽作为一种终产品或者前体物质 ,在食品和药物生产上的商业潜力非常巨大 ,从而促进了肽合成的研究和发展 .目前肽合成主要有 3种方法 :化学法、重组DNA技术、酶法 .每种方法都有其优点和缺点 .总体上来说 ,在工业上化学法仍然使用得最多 ,其热力学动力学模型已经很好地建立起来 ;重组 DNA技术 ,由于需要一个长期、昂贵的研究和发展阶段 ,而且在发酵阶段存在表达效率低和产品提取回收困难… 相似文献
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在先后以α-胰凝乳蛋白酶和和木瓜酶作催化剂的作用下,从C端的LeuNH2的氨基开始,逐个与N保护的氨基酸或其衍射生物缩合,合成了亮-脑啡肽色氨酸类似物-TyrGlyGly Trp LeuNH2.对酶的专一性、有机溶剂的选择和合成条件等进行了研究,在Z-TyrOMe和GlyGlyTrp LeuNH2的缩合反应中,比较了相转移法和均相法。上述两种酶的酶促接肽的供体以N-酰基氨基酸酯为好,比相相应的游离酸反应速度快,副反应少,如用嗜热菌蛋白酶,则以N-酰基氨基酸为好,酶促合成与从有机合成所得的产物相同。初步的体外实验表明合成的TyrGlyGlyTrpLeuNH2和天然的亮-脑啡肽对豚鼠回肠的收缩显示相同程度的鸦片样的抑制作用。 相似文献
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用磷酸三酯法在溶液中合成了两个带有3′-(S)-胸腺嘧啶基-4′-(R)-羟基-5′-(S)-羟甲基四氢呋喃的三脱氧核苷酸3和4。与三脱氧核苷酸(2)相比,化合物3和4对核酸酶S1具有更大的稳定性。 相似文献
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α—葡萄糖基—甜菊糖的酶促合成反应研究(Ⅰ) 总被引:1,自引:0,他引:1
研究了葡萄糖基转移酶GT-1催化甜菊糖转化为α-葡萄糖基-甜菊糖的各种影响因素,实验结果表明,甜菊糖的酶促转达到一定程度后,继续增大酶和淀粉用量及延长反应时间,对转化结果没有太多改善,经过处理后,甜菊糖的口味大为改善。 相似文献
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Papain immobilised on different types of polymeric supports was used for the synthesis of peptides in aqueous-organic solvent
mixtures. The effects of the nature of the polymer support, degree of crosslinking, nature and length of the spacer grouping
between the polymer backbone and the point of attachment of the enzyme, and reaction conditions like pH, concentration of
nucleophile and the immobilised enzyme content on the course of the synthesis were investigated. Divinylbenzene-crosslinked
polystyrene, divinylbenzenecrosslinked polyacrylamide and N,N′-methylene-bis-acrylamide-crosslinked polyacrylamide systems immobilised with papain were used for these studies. An increase in the length
of the spacer arm and an increase in hydrophilicity invariably resulted in an increase in the yield of the peptide synthesis.
Papain immobilised on polystyrene-PEG supports and tetraethyleneglycol-crosslinked polystyrene supports was determined to
be more efficient in effecting peptide synthesis when compared to other polystyrene-based supports. 相似文献
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Howard H. Weetall 《Applied biochemistry and biotechnology》1985,11(1):25-28
Esters of gallic acid were synthesized by enzymatic means using tannase fromAspergillus niger. Alcohols ranging from C1 through C12 and diols from C3 through C6 were tested and found to form esters in the presence of the enzyme. 相似文献
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Yi Quan Liua Hui Hui Li Yun Hua Yea Gu Yuan a Beijing National Laboratory for Molecular Sciences Key Laboratory of Bioorganic Chemistry Molecular Engineering of Ministry of Education 《中国化学快报》2009,20(3)
The interaction between HIV-I DNA and five cyclic peptides (CPI-CP5) was investigated using electrospray ionization mass spectrometry (ESI-MS). It revealed that CPI [c(Ala-Tyr-Leu-Ala-Gly)] and CP4 [c(Pro-D-Tyr-Leu-D-Ala-Gly)] have the higher binding affinity with the duplex DNA among the five cyclic peptides. 相似文献
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Sakayu Shimizu Kiyoshi Yamane Yoshiki Tani Hideaki Yamada 《Applied biochemistry and biotechnology》1983,8(3):237-247
A new and simple enzymatic method for the synthesis of flavin adenine dinucleotide (FAD) from flavin mononucleotide by the
transadenylylation reaction using microbial cells is described.
Among various microorganisms tested,Artherobacter globiformis IFO 12138 and two soil bacteria were selected as useful enzyme sources. Under suitable reaction conditions, the amount of
FAD synthesized was 2.25 μmol/mL with cells ofA. globiformis.
The transadenylylation reaction could be coupled with the ATP supplying system through a glycolysis process with yeast. 相似文献
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A process for the synthesis of CCK-8 tripeptide H-Gly-Trp-Met-OH catalyzed by immobilized enzyme was reported. Enzymes were used for the formation of peptide bonds and the removal of protecting group. Starting with phenylacetyl (PhAc) glycin, N-protected dipeptide PhAc-Gly-Trp-OMe was obtained by coupling PhAc-protected glycine carboxamidomethyl ester (OCam) with Trp-OMe catalyzed by immobilized papain in buffered ethyl acetate. Then the condensation between PhAc-Gly-Trp-OMe and Met-OEtoHC1 was carried out by immobilized α-chymotrypsin catalysis in solvent free system. Basic hydrolysis was followed getting PhAc-Gly-Trp-Met-OH. The PhAc-group was removed with penicillin G amidase and H-Gly-Trp-Met-OH was obtained in an overall yield of 43.9%. The reaction conversion of tripeptide in solvent free system was strongly affected by the system of basic salts added. The influence of the support materials used to deposit enzymes and structures of acyl donor and nucleophile on the reaction was also investigated. 相似文献
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We report the synthesis of Fmoc protected single amino acid chelates (SAAC) and their metal complexes. The modified amino acids are suitable for solid-phase peptide synthesis. The use of 4-hydroxymethylbenzoic acid AM (HMBA-AM) resin allows the nucleophilic cleavage of the peptide-metal complexes from the resin without decomplexation. 相似文献
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IntroductionEnzymaticpeptidesynthesishasdrawnmuchatten tionbecauseofitsadvantageofenzymestereospecificity ,mildreactionconditions ,minimumside chainprotectionandavoidanceofracemization .Butthestrictsubstratespecificityoftheenzymeslimitstheirapplications .… 相似文献
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The solid-phase synthesis of a series of model dipeptides containing various 3-(quinoxalin-6-yl)alanine analogues is described. The method involves formation of a quinoxaline heterocycle by condensation between an α-dicarbonyl compound and a β-(3,4-diaminophenyl)alanine residue, immobilized on a solid support. 相似文献
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《Tetrahedron letters》2004,45(6):1203-1205
Amino-acridine conjugates play an important role as biochemical probes and/or drugs. Solid-phase synthesis of such compounds suitable for library construction and biological screening is described. 相似文献
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Shimaa A.H. Abdel Monaim Gerardo A. Acosta Miriam Royo Ayman El-Faham Beatriz G. de la Torre Fernando Albericio 《Tetrahedron letters》2018,59(18):1779-1782
Cyclic homodetic peptides are very appealing for medicinal chemistry programs. In addition to the high efficiency and selectivity inherently associated with peptides, a cyclic structure totally formed by amide bonds increases their stability under physiological conditions. Here Fmoc-MeDbz-resin was studied for the preparation of these peptides. Our results demonstrate the usefulness of this strategy for the preparation of cyclic “head-to-side chain” peptides through cyclative cleavage (simultaneous cyclization and release from the resin). In contrast, for the synthesis of the “head-to-tail” counterparts, the cyclization-cleavage should be carried out in the presence of thiophenol. 相似文献