Structure-activity relationships of alpha-human atrial natriuretic peptide (alpha-hANP) analogs: role of charged groups in alpha-hANP.

To determine whether the addition of a methylene unit in the side chain of the Asp or Arg residue in alpha-human atrial natriuretic peptide (alpha-hANP) influences its biological activity, analogs of alpha-hANP, [Glu13]-alpha-hANP (7-28) (1), [Aad13]-alpha-hANP (7-28) (2), and [Harn]-alpha-hANP(7-28) (where n is any possible combination of 11, 14 and 27) (3-9), where the original Asp or Arg residue was replaced by a homo-amino acid, were synthesized by the solid-phase synthesis method. All the analogs were evaluated for their receptor binding, cyclic guanosine monophosphate (cGMP) accumulation activity in rat vascular smooth muscle cells (VSMC), and for vasorelaxant activity employing rat aorta. 1 and 2 were 0.9 and 0.03 times as potent as alpha-hANP (7-28), respectively, in binding. Har-containing analogs (3-9) were as potent as alpha-hANP (7-28) in binding. Among the Har-containing analogs, [Har11,14]-alpha-hANP (7-28) (6) and [Har11,27]-alpha-hANP (7-28) (7) were remarkably vasorelaxant active, being 4.2 and 5.3 times potent than alpha-hANP (7-28), respectively, in spite of relatively lower cGMP accumulation activity in the case of 7. The roles of the chargeable amino acid residues in biological activity are discussed.     

Solution-phase synthesis of alpha-rat atrial natriuretic peptide (alpha-rANP)

alpha-Rat atrial natriuretic peptide (alpha-rANP) was synthesized by assembling five peptide fragments in solution, followed by HF-dimethylselenide-m-cresol deprotection and subsequent air-oxidation. Synthetic alpha-rANP exhibited more potent diuretic and natriuretic activity in rats than synthetic alpha-hANP.     

Solution-phase synthesis of porcine brain natriuretic peptide (pBNP) using S-trimethylacetamidomethylcysteine

The hexadodecapeptide corresponding to the entire amino acid sequence of porcine brain natriuretic peptide (pBNP) was synthesized by assembling four segments in solution, followed by HF deprotection and subsequent oxidation to establish an intramolecular disulfide bridge. The synthesis using the newly developed S-trimethylacetamidomethylcysteine [Cys(Tacm)] derivative gave a better yield than that using the S-2,4,6-trimethylbenzylcysteine [Cys(Tmb)] derivative. The chick rectum relaxant activity of the synthetic pBNP was 2.9 times more potent than that of alpha-rat atrial natriuretic peptide (alpha-rANP).     

Synthesis and biological property of alpha-human atrial natriuretic peptide analogs with a constrained or stereochemically modified cyclic moiety

Conformationally restricted analogs of alpha-human atrial natriuretic peptide (alpha-hANP) containing L- or D-penicillamine, or D-cysteine in place of cysteine residues at positions 7 and 23 were synthesized by the liquid phase procedure. Their biological properties in the assays of receptor binding and cyclic guanosine monophosphate (cGMP) accumulation employing rat vascular smooth muscle cells (VSMC), vasorelaxant activity using rat isolated aorta were evaluated. We found that the constrained and/or stereochemically altered ring moiety generally did not influence the receptor binding activity, however, cGMP accumulation and vasorelaxant activities were quite sensitive to conformational perturbation. Furthermore, a lack of correlation between cGMP accumulation activity and vasorelaxant activity was observed. Dissociation between these activities was typical in the case of [DPen7,23]-alpha-hANP(7-28), which showed quite weak vasorelaxant activity in spite of its full cGMP accumulation and receptor binding potencies. This result suggests that cGMP accumulation alone is not sufficient to promote ANP-induced vasorelaxation, and that the other second messenger(s) may mediate this activity.     

Construction and use of two alpha-human atrial natriuretic peptide-fragment affinity chromatography columns in the isolation of C- and N-terminal epitope-specific antibodies for use in a prototype alpha-hANP biosensor.

Two alpha-human atrial natriuretic peptide (alpha-hANP) based affinity chromatography columns were produced by covalently immobilizing the C- and N-terminal epitopes of alpha-hANP. The stationary phase was made from a controlled-pore-glass bead solid support, which was silanized and treated with sulphosuccinimidyl 4-(maleimidomethyl)cyclohexyl carboxylate before the individual fragments were immobilized by substitution at their thiol groups. These columns were used to isolate alpha-hANP-specific antibodies from a goat anti-alpha-hANP serum, which were then further sorted according to their epitope specifity. These C- and N-terminal epitope-specific antibodies were in turn used as components in the construction of an alpha-hANP biosensor based on an enzyme-linked immunosorbent assay (ELISA) sandwich principle. Initial in vitro testing of the sensor using a physiological alpha-hANP solution showed a reproducible response to the peptide. There is to date no other equally fast, sensitive and precise method available to detect this peptide. This alpha-hANP sensor may prove to be an invaluable aid in human medicine as a monitor of patient status during transplant surgery, for example, an area inaccessible to radioimmunoassay and normal ELISA techniques.     

超高效液相色谱-质谱联用法监测人心房钠尿肽的化学合成

多肽作为神经递质、激素、受体等参与和调节许多重要的生命过程。随着对多肽结构与功能认识的深入,化学合成多肽在生物医药、生命分析等领域显示了重要价值。人心房钠尿肽(ANP)是一种由28个氨基酸组成的多肽类激素,其含量和代谢异常与心血管疾病、癌症等密切相关。针对ANP重要的生理功能,该文开展了ANP化学合成及其过程的监测与优化,设计了集固相合成线性直链多肽和液相氧化成环为一体的策略。基于高效液相色谱的分离性能和多级质谱的结构鉴定能力,建立了超高效液相色谱-串联质谱(UHPLC-MS/MS)分析新方法,对固相合成产物进行了分离分析,并对液相氧化方法进行了筛选和优化,最终分离纯化得到了目标多肽,为人心房钠尿肽的高效化学合成及氧化成环反应提供借鉴。     

Solution-phase parallel synthesis of a library of delta(2)-pyrazolines

A parallel synthesis of a library (80 members) of 2-pyrazolines in solution phase is described. The 2-pyrazoline core was accessed through the [3 + 2] cycloaddition of nitrilimines with enoyl oxazolidinones. The cycloaddition provided two regioisomers, the major product being the C regioisomer. The oxazolidinone moiety was further reduced to the primary alcohol, producing another library of 5-hydroxymethyl-2-pyrazolines. The Lipinski profiles and calculated ADME properties of the compounds are also reported.     

Solution-phase parallel synthesis of spirohydantoins

Spirohydantoins are considered privileged structures, making them attractive for the preparation of compound libraries with the potential for diverse biological activity. However, very few modifications of this scaffold have been reported to date. The spirohydantoin template was elaborated into a library of 168 compounds through a two-step solution-phase parallel synthesis starting from various N-substituted piperidinones. The Strecker reaction was employed to generate alpha-amino nitriles from aniline and TMSCN (or KCN). Subsequent reaction of the anilido nitrogen with a diverse set of isocyanates, followed by refluxing under acidic conditions, afforded the title library in high yield and purity.     

Solution-phase template approach for the synthesis of Cu(2)S nanoribbons

In this paper, we have developed a solution-phase template approach to synthesize Cu(2)S nanoribbons for the first time. Bi(2)S(3) nanoribbons act as both template and reactant when treated with small CuCl particles, generating Cu(2)S nanoribbons with the assistance of the solvent ethanol. Nanoribbons with different compositions of Bi(2)S(3) and Cu(2)S also could be obtained through controlling the reaction time. This kind of template method is expected to be a general template approach due to its slow reaction rate and simplicity.     

Solution-phase library synthesis of furanoses

The solution-phase synthesis of amido-, urea-, and aminofuranoses was achieved. Alkylated furanose aldehydes were treated with primary amines in the presence of sodium triacetoxyborohydride to give secondary amines. Subsequent acylation with acid chlorides and isocyanates afforded amidofuranoses and ureafuranoses, respectively. Second, reductive amination of furanose aldehydes with secondary amines yielded tertiary amines. The resulting acetonides were treated with alcohols in the presence of acid to yield mixed acetals. In the library syntheses, functionalized scavenger resins were used in the purification of intermediates and products.     

Solution-phase parallel synthesis of substituted benzimidazoles

A solution-phase parallel synthesis of o-phenylenediamines is described. These intermediates were then subsequently converted to benzimidazole scaffolds (three-point diversity) in excellent purities and yields. High-throughput purification of this multistep synthetic sequence was accomplished using polymer-bound scavengers and reagents and liquid-liquid extraction protocols.     

Solution-phase automated synthesis of tripeptide derivatives

An improved general method for automated synthesis of tripeptides was developed, in which methanesulfonic acid (MSA) was used in place of trifluoroacetic acid (TFA), thus making it possible to avoid, 1) corrosion of the apparatus by strong acid vapor, 2) formation of emulsions, and 3) use of the restricted solvent, dichloromethane. As an application of the automated synthesis apparatus, 216 fragment tripeptide derivatives were synthesized systematically using the MSA method, in excellent yield and with increased efficiency.     

Synthesis and secretion of human atrial natriuretic peptide in Saccharomyces cerevisiae

A chemically synthesized alpha-hANP gene was inserted into plasmid YFD18, which was an expression-secretion vector of yeast. The recombinant then transformed in the yeast Y33. The expression level of yeast transformants was about 700 micrograms ANP/L detected by RIA. More than 99% of expression products were secreted in the culture medium. N-terminal analysis of purified product showed that the first 4 amino acid residues of alpha-hANP were deleted.     

脑钠素与充血性心力衰竭

制备了一种三维多孔镍钼硫化物纳米花修饰碳纳米管（CNT）的复合材料（NiMoS@CNT）. 通过扫描电子显微镜和X射线衍射表征所合成材料的形貌和结构. 利用循环伏安法和计时电流法对所制备材料的电化学催化性能进行研究. 基于NiMoS@CNT对过氧化氢（H₂O₂）优异的电催化性能,构建了一种检测脑利钠肽的夹心型电化学传感器. 在最优条件下,电流响应强度和脑利钠肽质量浓度的对数在0.20~20 ng/mL范围内呈线性关系. 结果表明免疫传感器具有高的灵敏度、选择性和稳定性,可用于实际样品的检测.     

Solution-phase parallel synthesis of 2,3-dihydro-1,5-benzothiazepin-4(5H)-ones

Practical and efficient parallel methods have been developed for the synthesis of 7,8-disubstituted 2,3-dihydro-1,5-benzothiazepin-4(5H)-ones and 3,7,8-trisubstituted 2,3-dihydro-1,5-benzothiazepin-4(5H)-ones. This benzothiazepin-4(5H)-one skeleton possesses three or four diversity points. Furthermore, three novel tricycles integrating a benzothiazepin-4(5H)-one scaffold with other privileged structures, such as benzimidazole, benzimidazolone, and thio-benzimidazole, were also developed. The synthetic strategy provides an efficient way to access the benzothiazepinone core, starting from commercially available 1,5-difluoro-2,4-dinitrobenzene (DFDNB), and also allows further derivation of the strategically anchored functionalities.     

Solution-phase synthesis of spherical zinc sulfide nanostructures

A facile solution-phase method has been developed to synthesize specially hollow and solid ZnS nanospheres. High-resolution TEM images on the nanospheres suggest their formation via the oriented aggregation of the primary ZnS nanocrystals. The morphology and size of the ZnS nanospheres can also be tuned easily by controlling the experimental conditions. These special spherical structures are very easily encapsulated within a uniform silica layer without any surface modification, suggesting potential applications in biochemistry and biodiagnostics.     

Solution-phase parallel synthesis of highly diverse spiroisoxazolinohydantoins

Practical and efficient solution-phase parallel synthesis of spiroisoxazolinohydantoins under mild conditions has been developed. This spiroisoxazolinohydantoin skeleton possesses three diversity points. The key intermediate, exo-methylenehydantoin bearing two positions of diversification, is prepared via a one-pot synthetic route from N-substituted methyl ester serine. Employing various alkyl halides, isocyanates, and oximes, this chemistry is applied in the generation of an 18-member demonstration library with high yield, high purity and excellent regioselectivity.     

Solution-phase parallel synthesis of carbamates using polymer-bound N-hydroxysuccinimide

[formula: see text] A convenient method for the synthesis of carbamates using polymer-supported N-hydroxysuccinimide is described. Various carbamates were synthesized in highly pure form without the need for chromatographic purification. This new "catch and release"-type solid-phase synthesis should be useful for combinatorial synthesis of various carbamates.