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Peptide crystal growth via vapor diffusion. Crystal structure of glycyl-L-tyrosyl-L-alanine dihydrate. 通过蒸汽扩散生长肽晶体。二水合甘酰基-酪氨酸-丙氨酸的晶体结构。
D S Eggleston, P W Baures

The structure of a dihydrated form of glycyl-L-tyrosyl-L-alanine (GYA) has been determined as part of a series of peptide structural investigations and development of microscale vapor diffusion experiments for peptide crystal growth. Crystals were grown by the hanging-drop method against sodium acetate. The tripeptide is a zwitterion in the crystal, adopting an extended conformation through glycine, a nearly perpendicular bend at tyrosine and a reverse turn for the C-terminal carboxylate. Principal backbone torsion angles are psi 1 175(1) degrees, omega 2 173(1) degrees, phi 2 -119(1) degrees, psi 2 120(1) degrees, omega 3 172(1) degrees, phi 3 -73(1) degrees, psi 31 -9(1) degrees, psi 32 171(1) degrees. The tyrosyl side chain adopts an unusual orientation (chi 1/2 = -86(1) degrees). The relationship of the GYA.2H2O structure to GYA sequences in proteins is examined, particularly as regards its helix-forming potential. Crystal data: C14H19N3O4.2H2O, M(r) = 345.36, orthorhombic, P2(1)2(1)2(1), a = 4.810 (4), b = 11.400(7), c = 30.162(23)A, V = 1653.8(24)A-3, Z = 4, Dx = 1.387 Mgm-3, lambda(CuK- alpha) = 1.540 A, mu = 9.053 mm-1, F(000) = 736, T = 199 K, R = 0.041 for 1458 observations with I greater than or equal to 3 sigma(I).

二水合形式的甘酰基- l-酪氨酸- l-丙氨酸(GYA)的结构已经确定,作为肽结构研究和微尺度蒸汽扩散实验的一部分,用于肽晶体生长。用悬滴法在乙酸钠环境下生长晶体。该三肽在晶体中为两性离子,在甘氨酸处呈延伸构象,在酪氨酸处呈几乎垂直的弯曲,在c端羧酸盐处呈相反的弯曲。主要的骨干扭力角是psi 1 175(1)度,omega 2 173(1)度,phi 2 -119(1)度,psi 2 120(1)度,omega 3 172(1)度,psi 3 -73(1)度,psi 31 -9(1)度,psi 32 171(1)度。酪氨酸侧链的取向不同寻常(chi 1/2 = -86(1)度)。研究了GYA. 2h2o结构与蛋白质中GYA序列的关系,特别是关于其螺旋形成潜力。晶体数据:C14H19N3O4.2H2O, M(r) = 345.36,正交,P2(1)2(1)2(1), a = 4.810 (4), b = 11.400(7), c = 30.162(23) a, V = 1653.8(24) a -3, Z = 4, Dx = 1.387 mg -3, lambda(CuK- alpha) = 1.540 a, mu = 9.053 mm-1, F(000) = 736, T = 199 K, r = 0.041, I大于等于3 sigma(I)。
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引用次数: 0
N-alkoxycarbonyl-glutamic and aspartic acids. Studies on the activation and cyclodehydration and side-reaction encountered in analysis of glutamic acid using Fmoc-chloride. n -烷氧羰基谷氨酸和天冬氨酸。fmoc -氯化物分析谷氨酸时的活化、环脱水及副反应研究。
F M Chen, N L Benoiton

N-Alkoxycarbonylaminodicarboxylic acids were reacted in dichloromethane with N-ethyl-N'-(dimethylaminopropyl)carbodiimide hydrochloride, and with methyl chloroformate in the presence of N-methylmorpholine. Removal of secondary products by washing the mixtures with aqueous solutions gave good yields of the pure crystalline internal anhydrides. Anhydrides of N-benzyloxycarbonyl- (Z) and N-9-fluorenylmethoxycarbonyl-(Fmoc) L-glutamic and L-aspartic acids and of N-tert.-butoxycarbonyl-L-aspartic acid were prepared in this way. The compounds were shown to be amenable to normal phase high-performance liquid chromatography (NP-HPLC) on a CN-column using tert.-butanol-hexane as solvent. The products of the reactions of Z- and Fmoc-glutamic acid with hot acetic anhydride were examined by nuclear magnetic resonance and NP-HPLC before and after methanolysis in an attempt to establish if any of the corresponding pyroglutamates were formed. The reaction of Fmoc-chloride with Fmoc-glutamate was examined for the same reason. It is concluded that the side product generated during the reaction of Fmoc-chloride with glutamic acid which is used for analysis of the latter is the N-protected internal anhydride and not the pyroglutamate as reported in the literature.

n -烷氧羰基氨基二羧酸在二氯甲烷中与n -乙基- n '-(二甲氨基丙基)卡二亚胺盐酸盐以及在n -甲基吗啡啉存在下与氯甲酸甲酯反应。用水溶液洗涤混合物,除去二次产物,得到了纯度较高的结晶内酸酐。n -苄基氧羰基-(Z)和n -9-氟酰甲氧羰基-(Fmoc) l-谷氨酸和l-天冬氨酸和n -叔丁基的酸酐。用此方法制备了-丁氧羰基- l-天冬氨酸。结果表明,这些化合物可以用正相高效液相色谱法(NP-HPLC)在n -色谱柱上使用。-丁醇-己烷为溶剂。用核磁共振和NP-HPLC检测了Z-和fmoc -谷氨酸与热乙酸酐反应前后的产物,试图确定是否有相应的焦谷氨酸生成。基于同样的原因,研究了氯化物与谷氨酸盐的反应。结果表明,用于分析谷氨酸的Fmoc-chloride与谷氨酸反应产生的副产物是n保护的内酸酐,而不是文献中报道的焦谷氨酸。
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引用次数: 0
Survey of conformational role of ester bonds in a cyclic depsipeptide. Study on cyclo(-L-Ala-L-Hmb-)2 by energy calculation and NMR spectroscopy. 环状沉积肽中酯键构象作用的研究。用能量计算和核磁共振光谱法研究环(- l - ala - l - hmb -)2。
T Kato, H Mizuno, S Lee, H Aoyagi, H Kodama, N Go, T Kato

The effect of ester bond on the conformation of peptide molecule was studied by designing and synthesizing a model tetradepsipeptide cyclo(-L-Ala-L-Hmb-)2 and by analyzing the conformation both theoretically and experimentally. Theoretical analysis showed that both ester and peptide bonds in the calculated low-energy conformations within 3 kcal/mol of the global minimum take a trans but distorted configuration. The distortion is larger in ester bonds than in peptide bonds. Further, the four carbonyls project from one side of the plane of the cyclic backbone, whereas the side chains project from the other side. These results are consistent with the experimental results obtained by NMR measurement; first, the coupling constant deduced from 1H-NMR species in DMSO-d6 is consistent with the dihedral angles of the calculated low-energy conformations; second, results of NOE measurement can reproduce the calculated configuration of the carbonyls and side chains. From the consistency between theoretical and experimental results, it is concluded that this model tetradepsipeptide takes an all-trans backbone conformation in solution and this backbone conformation is stabilized by large distortion in the ester bond, which compensates the strain resulted from the 12-membered cyclic backbone structure consisting only of L-residues.

通过设计和合成四沉积肽环(- l - ala - l - hmb -)2模型,并对其构象进行理论和实验分析,研究了酯键对肽分子构象的影响。理论分析表明,在全局最小值3 kcal/mol范围内,计算得到的低能构象中的酯键和肽键均为反式扭曲构象。酯键的畸变比肽键大。此外,四个羰基从环主链平面的一侧突出,而侧链从另一侧突出。这些结果与核磁共振测量的实验结果一致;首先,从DMSO-d6的1H-NMR组分推导出的耦合常数与计算出的低能构象的二面角一致;其次,NOE测量结果可以再现计算出的羰基和侧链的构型。从理论和实验结果的一致性来看,该模型四沉积肽在溶液中呈全反式主链构象,该主链构象由于酯键的大畸变而稳定,补偿了仅由l-残基组成的12元环状主链结构所造成的应变。
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引用次数: 0
Conformation of a neurokinin antagonist in solution. 2D NMR and restrained molecular dynamics study. 神经激肽拮抗剂在溶液中的构象。二维核磁共振和约束分子动力学研究。
J A Malikayil, S L Harbeson

The hexapeptide [cyclo(Leu1 psi(CH2NH2)Leu2-Gln3-Trp4-Phe5-Gly6)]+1 is a potent antagonist of neurokinin A activity in tissues of hamster urinary bladder. The solution conformation of this cyclic hexapeptide has been characterized by the combined use of two dimensional nuclear magnetic resonance spectroscopy and restrained molecular dynamics. The proton spectrum of the peptide was fully assigned by the sequential assignment procedure. Interproton distances were derived from crosspeak volumes in two dimensional Nuclear Overhauser Effect spectra, and dihedral angles were calculated from appropriate coupling constants. Temperature coefficients of the amide protons were determined. Restrained molecular dynamics simulations were carried out using the backbone interproton distances as constraints. During 210 ps of restrained molecular dynamics the peptide interconverted among three closely related families of conformations. These interconversions occurred at picosecond timescales under the simulation conditions.

六肽[cyclo(Leu1 psi(CH2NH2)Leu2-Gln3-Trp4-Phe5-Gly6)]+1是仓鼠膀胱组织中神经激肽a活性的有效拮抗剂。结合二维核磁共振波谱和约束分子动力学对该环六肽的溶液构象进行了表征。肽的质子谱通过顺序赋值程序被完全赋值。在二维核超豪瑟效应谱中,质子间距离由串声体积导出,二面角由适当的耦合常数计算得到。测定了酰胺质子的温度系数。以主质子间距离为约束条件,进行了约束分子动力学模拟。在210 ps的抑制分子动力学过程中,肽在三个密切相关的构象家族之间相互转化。在模拟条件下,这些转换发生在皮秒时间尺度上。
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引用次数: 0
Binding and spectroscopic properties of ostrich neurophysins. Probing the role of residue 35 at the monomer-monomer interface. 鸵鸟神经毒素的结合与光谱特性。探讨残基35在单体-单体界面上的作用。
E Breslow, T LaBorde, H S Saayman, W Oelofsen, R J Naudé

Binding and spectroscopic properties of ostrich neurophysins were examined with emphasis on the behavior of Tyr-35, a residue that provides a potential probe of the monomer-monomer interface and of allosteric interrelationships between this region and the binding site. Mesotocin-associated ostrich neurophysin was found to bind oxytocin and related peptides with affinities comparable to the mammalian proteins, but induced a significantly different optical activity in bound peptides than the mammalian proteins. Gel-filtration studies indicated higher dimerization constants for the ostrich neurophysins than for the bovine neurophysins. Consistent with this, Tyr-35 was found to be largely buried, as monitored by tyrosine titration and lack of reactivity towards tetranitromethane under non-denaturing conditions. Reaction of Tyr-35 of the mesotocin-associated protein with tetranitromethane under denaturing conditions, followed by refolding, allowed isolation of an active product with an altered interface region as partially evidenced by its titration properties and consistent with its markedly altered CD spectrum. Comparison of the CD spectra of the modified and native proteins and analysis of pH effects indicated the contribution of Tyr-35 to an unusual 237 nm band in the mesotocin-associated protein. Small shifts in the 350 nm CD band of nitrated Tyr-35 on binding peptide and apparent effects of nitration on the induced optical activity in bound peptide provided evidence of at least weak structural communication between Tyr-35 and the binding site. However, no significant effect of nitration on binding affinity was observed, suggesting that, in the mesotocin-associated protein, the region around residue 35 is not a stringent modulator of the thermodynamic behavior of the binding site.

研究了鸵鸟神经磷脂的结合特性和光谱特性,重点研究了tyr35的行为,这是一种残基,为研究单体界面和该区域与结合位点之间的变构相互关系提供了潜在的探针。研究发现,与催产素相关的鸵鸟神经physin结合催产素和相关肽的亲和力与哺乳动物蛋白相当,但在结合肽中诱导的光学活性明显不同于哺乳动物蛋白。凝胶过滤研究表明鸵鸟神经磷脂的二聚化常数高于牛神经磷脂。与此一致的是,通过酪氨酸滴定和在非变性条件下对四硝基甲烷缺乏反应性的监测,发现Tyr-35大部分被掩埋。在变性条件下,中介素相关蛋白的tyr35与四硝基甲烷反应,然后再折叠,可以分离出具有改变界面区域的活性产物,其滴定特性部分证明了这一点,并与其显着改变的CD谱相一致。比较修饰蛋白和天然蛋白的CD光谱以及pH效应分析表明,Tyr-35对中生激素相关蛋白中一个不寻常的237 nm波段有贡献。硝化后的tyr35在结合肽上350 nm CD波段的微小位移以及硝化对结合肽诱导的光学活性的明显影响,证明了tyr35与结合位点之间至少存在微弱的结构通信。然而,没有观察到硝化对结合亲和力的显著影响,这表明,在中生毒素相关蛋白中,残基35周围的区域并不是结合位点热力学行为的严格调节剂。
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引用次数: 0
C9 conformation of N-(N alpha-[(tert.-butyloxy)-carbonyl]-L-alanyl)-N,N'-dicyclohexylu rea in solid and solution. N-(N α -[(叔丁氧基)羰基]- l -丙烯基)-N,N'-双环己基脲在固体和溶液中的C9构象。
C Sudarsanakumar, S Srinivasan, R Jayakumar

An X-ray diffraction study was carried out on a single crystal of N-(N alpha-[(tert.-butyloxy)-carbonyl]-L-alanyl)-N,N'-dicyclohexylur ea belonging to the tetragonal space group P4(1)2(1)2, having cell dimensions a = b = 10.102(3) A, c = 46.067(7) A, V = 4701.2 A3, Z = 8. The crystal structure was solved by direct methods and refined to an R value of 0.056 for 1602 unique reflections with I greater than 2.5 sigma(I). Crystal structure analysis shows the presence of an intramolecular N-H ... O=C H-bond stabilizing the molecule in a folded form similar to that of a beta turn, forming a nine-membered ring. IR and 1H-NMR studies in CDCl3 solution confirm the stable folded conformation found in the crystalline state, as well as the existence of N-H ... O=C H-bonds in the title compound, as in peptides.

用x射线衍射研究了N-(N α -[(叔丁氧基)羰基]- l -丙烯基)-N,N'-双环己基a单晶,该单晶属于四方空间群P4(1)2(1)2,晶胞尺寸a = b = 10.102(3) a, c = 46.067(7) a, V = 4701.2 A3, Z = 8。用直接法求解晶体结构,得到1602个I大于2.5 σ (I)的唯一反射的R值为0.056。晶体结构分析表明分子内存在N-H…O=C氢键稳定分子的折叠形式类似于β转,形成一个九元环。在CDCl3溶液中的IR和1H-NMR研究证实了在晶体状态下发现的稳定的折叠构象,以及N-H…在标题化合物中,如肽中的O=C氢键。
{"title":"C9 conformation of N-(N alpha-[(tert.-butyloxy)-carbonyl]-L-alanyl)-N,N'-dicyclohexylu rea in solid and solution.","authors":"C Sudarsanakumar,&nbsp;S Srinivasan,&nbsp;R Jayakumar","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>An X-ray diffraction study was carried out on a single crystal of N-(N alpha-[(tert.-butyloxy)-carbonyl]-L-alanyl)-N,N'-dicyclohexylur ea belonging to the tetragonal space group P4(1)2(1)2, having cell dimensions a = b = 10.102(3) A, c = 46.067(7) A, V = 4701.2 A3, Z = 8. The crystal structure was solved by direct methods and refined to an R value of 0.056 for 1602 unique reflections with I greater than 2.5 sigma(I). Crystal structure analysis shows the presence of an intramolecular N-H ... O=C H-bond stabilizing the molecule in a folded form similar to that of a beta turn, forming a nine-membered ring. IR and 1H-NMR studies in CDCl3 solution confirm the stable folded conformation found in the crystalline state, as well as the existence of N-H ... O=C H-bonds in the title compound, as in peptides.</p>","PeriodicalId":14204,"journal":{"name":"International journal of peptide and protein research","volume":"39 4","pages":"285-90"},"PeriodicalIF":0.0,"publicationDate":"1992-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"12515565","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Studies on cell-clearing activity in alpha-lactalbumin. Effects of calcium removal on activity and conformation. α -乳清蛋白细胞清除活性的研究。钙去除对活性和构象的影响。
F H White

Effects of calcium removal on the cell-clearing activity of alpha-lactalbumin (alpha-LA) and concomitant changes in conformational structure have been investigated as part of a continuing study of the activity found earlier [McKenzie, H.A. & White, F.H., Jr. (1987) Biochem. Int. 14, 347]. This activity is similar to that of lysozyme, whereby lysis of the bacterial cell wall is catalyzed. However, the specific activity of alpha-LA is on the order of 10(-6) that of lysozyme. Under conditions where activities of apo and native alpha-LA were approximately linear functions of the protein concentration, the maximal ratio of apo to native activity was 5.7:1, determined by comparison of second order velocity constants. The CD spectrum of apo alpha-LA is intermediate between that of the A state and the native protein. By NMR, the conformation of apo alpha-LA is similar to, but distinctly different from, that of the native protein. The apo form did not revert completely to the native state when Ca(II) was resupplied, consistent with a role for this cation in folding. It is suggested that the activity increase may result from a diminished constriction of the "cleft" region in alpha-LA.

钙去除对α -乳清蛋白(α -la)的细胞清除活性的影响以及伴随的构象结构变化已经被研究作为早期发现的活性的持续研究的一部分[McKenzie, H.A. & White, f.h., Jr. (1987) Biochem]。Int. 14, 347]。这种活性类似于溶菌酶,从而催化细菌细胞壁的裂解。而α - la的比活性是溶菌酶的10(-6)量级。在载脂蛋白和天然α - la活性与蛋白浓度近似成线性关系的条件下,载脂蛋白与天然α - la活性的最大比值为5.7:1。载脂蛋白α - la的CD谱介于A态和天然蛋白的CD谱之间。通过核磁共振,载脂蛋白α - la的构象与天然蛋白相似,但又有明显不同。当Ca(II)被补充时,载脂蛋白形式并没有完全恢复到原始状态,这与该阳离子在折叠中的作用是一致的。这表明,活性增加可能是由于α - la“裂口”区域收缩减少所致。
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引用次数: 0
Conformational investigation of alpha, beta-dehydropeptides. Part III. Molecular and crystal structure of acetyl-L-prolyl-alpha, beta-dehydrovaline methylamide. 脱氢肽的构象研究。第三部分。乙酰- l-脯氨酸- α, β -去氢缬氨酸甲酰胺的分子和晶体结构。
E Ciszak, G Pietrzyński, B Rzeszotarska

The crystal structure of Ac-Pro-delta Val-NHCH3 was examined to determine the influence of the alpha,beta-dehydrovaline residue on the nature of peptide conformation. The peptide crystallizes from methanol-diethyl ether solution at 4 degrees in needle-shaped form in orthorhombic space group P2(1)2(1)2(1) with a = 11.384(2) A, b = 13.277(2) A, c = 9.942(1) A, V = 1502.7(4) A3, Z = 4, Dm = 1.17 g.cm-3 and Dc = 1.18 g.cm-3. The structure was solved by direct methods using SHELXS-86 and refined to an R value of 0.057 for 1922 observed reflections. The peptide is found to adopt a beta-bend between the type I and the type III conformation with phi 1 = -68.3(4) degrees, psi 1 = -20.1(4) degrees, phi 2 = -73.5(4) degrees and psi 2 = -14.1(4) degrees. An intramolecular hydrogen bond between the carbonyl oxygen of ith residue and the NH of (i + 3)th residue stabilizes the beta-bend. An additional intermolecular N...O hydrogen bond joins molecules into infinite chains. In the literature described crystal structures of peptides having a single alpha,beta-dehydroamino acid residue in the (i + 2) position and forming a beta-bend reveal a type II conformation.

研究了Ac-Pro-delta Val-NHCH3的晶体结构,以确定α, β -脱氢缬氨酸残基对肽构象性质的影响。该肽在4度甲醇-乙醚溶液中结晶,在正交空间群P2(1)2(1)2(1)中呈针状结晶,a = 11.384(2) a, b = 13.277(2) a, c = 9.942(1) a, V = 1502.7(4) A3, Z = 4, Dm = 1.17 g.cm-3, Dc = 1.18 g.cm-3。利用SHELXS-86直接求解了该结构,并对1922年观测到的反射进行了细化,R值为0.057。该肽被发现在I型和III型构象之间采用β弯曲,phi 1 = -68.3(4)度,psi 1 = -20.1(4)度,phi 2 = -73.5(4)度和psi 2 = -14.1(4)度。残基i的羰基氧和残基(i + 3)的NH之间的分子内氢键稳定了β弯曲。一个额外的分子间N…氢键将分子连接成无限的链。在文献中描述了在(i + 2)位置具有单个α、β -脱氢氨基酸残基并形成β -弯曲的肽的晶体结构,揭示了II型构象。
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引用次数: 0
Glycoconjugates of opioid peptides. Synthesis and biological activity of [Leu5]enkephalin related glycoconjugates with amide type of linkage. 阿片肽的糖缀合物。[Leu5]脑啡肽相关酰胺型糖缀合物的合成及生物活性研究。
L Varga-Defterdarović, S Horvat, N N Chung, P W Schiller

Three N-glycoconjugates of the general formula H-Tyr-Gly-Gly-Phe-Leu-NH-R (R = carbohydrate residue) were synthesized in order to determine the influence of some carbohydrate molecules (6-amino-6-deoxy-D-glucopyranose, 2-amino-2-deoxy-D-glucopyranose, beta-D-glucopyranosylamine) on the biological activity, conformation, and stability of the opioid pentapeptide [Leu5]enkephalin. For the preparation of this compound different methods of peptide synthesis (active ester and mixed anhydride) were investigated. In comparison with [Leu5]enkephalin, all three N-glycoconjugates showed higher potency in the guinea pig ileum assay and lower potency in the mouse vas deferens assay, indicating a decrease in delta opioid receptor selectivity.

为了确定一些碳水化合物分子(6-氨基-6-脱氧-d -葡萄糖吡喃糖、2-氨基-2-脱氧-d -葡萄糖吡喃糖、β -d -葡萄糖吡喃胺)对阿片五肽[Leu5]脑啡肽的生物活性、构象和稳定性的影响,合成了3种通式h - tyr -gly -gly - ph - leu - nh -R (R =碳水化合物残基)的n -糖缀合物。为制备该化合物,研究了不同的肽合成方法(活性酯和混合酸酐)。与[Leu5]脑啡肽相比,这三种n -糖缀合物在豚鼠回肠实验中表现出更高的效力,而在小鼠输精管实验中表现出更低的效力,表明δ阿片受体选择性降低。
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引用次数: 0
Side reactions in solid phase synthesis of histidine-containing peptides. Characterization of two major impurities by sample displacement chromatography and FAB-MS. 含组氨酸肽固相合成中的副反应。两种主要杂质的样品置换色谱和FAB-MS表征。
A Pessi, V Mancini, P Filtri, L Chiappinelli

The flow-polyamide synthesis of a histidine-containing sequence (Ac-YDNVLDHLTGR) produced two major impurities which were isolated through Sample Displacement Chromatography and characterized by Fast Atom Bombardment-mass analysis. The impurities correspond to the sequence Ac-YDNVLDH, and to a peptide with the Asp residue cyclized to a succinimide. The latter side-reaction took place during the acetylation procedure, and demands attention where capping procedures are planned in the synthesis of Asp-His sequences.

含组氨酸序列(Ac-YDNVLDHLTGR)的流动聚酰胺合成产生了两个主要杂质,通过样品置换色谱分离,并通过快速原子轰-质量分析对其进行了表征。这些杂质对应于Ac-YDNVLDH序列和一个Asp残基环化成琥珀酰亚胺的肽。后一种副反应发生在乙酰化过程中,需要注意在Asp-His序列合成中计划的盖帽程序。
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引用次数: 0
期刊
International journal of peptide and protein research
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