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1815618-15-5,CART(55-76), rat,Ile-Pro-Ile-Tyr-Glu-Lys-Lys-Tyr-Gly-Gln-Val-Pro-Met-Cys-Asp-Ala-Gly-Glu-Gln-Cys-Ala-Val(Disulfide bond),IPIYEKKYGQVPMCDAGEQCAV,杭州专肽生物的产品

CART(55-76), rat

Intracerebroventricular administration of this CART fragment inhibited normal and NPY-induced feeding in rats whereas injection of an antibody to it stimulated feeding. The anorexigenic fragment is also called CART 82-103.

编号:197640

CAS号:1815618-15-5

单字母:H2N-IPIYEKKYGQVPMCDAGEQCAV-OH(Disulfide Bridge:C14-C20)

纠错
  • 编号:197640
    中文名称:CART(55-76), rat
    英文名:CART(55-76), rat
    CAS号:1815618-15-5
    单字母:H2N-IPIYEKKYGQVPMCDAGEQCAV-OH(Disulfide Bridge:C14-C20)
    三字母:H2N-Ile-Pro-Ile-Tyr-Glu-Lys-Lys-Tyr-Gly-Gln-Val-Pro-Met-Cys-Asp-Ala-Gly-Glu-Gln-Cys-Ala-Val-OH(Disulfide Bridge:Cys14-Cys20)
    氨基酸个数:22
    分子式:C107H166N26O33S3
    平均分子量:2440.81
    精确分子量:2439.13
    等电点(PI):9.97
    pH=7.0时的净电荷数:3.91
    平均亲水性:-0.12777777777778
    疏水性值:-0.15
    外观与性状:白色粉末状固体
    消光系数:2980
    来源:人工化学合成,仅限科学研究使用,不得用于人体。
    纯度:95%、98%
    盐体系:可选TFA、HAc、HCl或其它
    生成周期:2-3周
    储存条件:负80℃至负20℃
    标签:二硫键环肽    CARTS   

  • Intracerebroventricular administration of this CART fragment inhibited normal and NPY-induced feeding in rats whereas injection of an antibody to it stimulated feeding. The anorexigenic fragment is also called CART 82-103.

    二硫键广泛存在与蛋白结构中,对稳定蛋白结构具有非常重要的意义,二硫键一般是通过序列中的2个Cys的巯基,经氧化形成。
     

    形成二硫键的方法很多:空气氧化法,DMSO氧化法,过氧化氢氧化法等。
     

    二硫键的合成过程,  可以通过Ellman检测以及HPLC检测方法对其反应进程进行监测。  
       

    如果多肽中只含有1对Cys,那二硫键的形成是简单的。多肽经固相或液相合成,然后在pH8-9的溶液中进行氧化。      
     

    当需要形成2对或2对以上的二硫键时,合成过程则相对复杂。尽管二硫键的形成通常是在合成方案的最后阶段完成,但有时引入预先形成的二硫化物是有利于连合或延长肽链的。通常采用的巯基保护基有trt, Acm, Mmt, tBu, Bzl, Mob, Tmob等多种基团。我们分别列出两种以2-Cl树脂和Rink树脂为载体合成的多肽上多对二硫键形成路线:
     

    二硫键反应条件选择    
     

     二硫键即为蛋白质或多肽分子中两个不同位点Cys的巯基(-SH)被氧化形成的S-S共价键。 一条肽链上不同位置的氨基酸之间形成的二硫键,可以将肽链折叠成特定的空间结构。多肽分 子通常分子量较大,空间结构复杂,结构中形成二硫键时要求两个半胱氨酸在空间距离上接近。 此外,多肽结构中还原态的巯基化学性质活泼,容易发生其他的副反应,而且肽链上其他侧链 也可能会发生一系列修饰,因此,肽链进行修饰所选取的氧化剂和氧化条件是反应的关键因素, 反应机理也比较复杂,既可能是自由基反应,也可能是离子反应。      

    反应条件有多种选择,比如空气氧化,DMSO氧化等温和的氧化过程,也可以采用H2O2,I2, 汞盐等激烈的反应条件。
     

    空气氧化法: 空气氧化法形成二硫键是多肽合成中最经典的方法,通常是将巯基处于还原态的多肽溶于水中,在近中性或弱碱性条件下(PH值6.5-10),反应24小时以上。为了降低分子之间二硫键形成的可能,该方法通常需要在低浓度条件下进行。
     

    碘氧化法:将多肽溶于25%的甲醇水溶液或30%的醋酸水溶液中,逐滴滴加10-15mol/L的碘进行氧化,反应15-40min。当肽链中含有对碘比较敏感的Tyr、Trp、Met和His的残基时,氧化条件要控制的更精确,氧化完后,立即加入维生素C或硫代硫酸钠除去过量的碘。 当序列中有两对或多对二硫键需要成环时,通常有两种情况:
     

    自然随机成环:       序列中的Cys之间随机成环,与一对二硫键成环条件相似;
     

    定点成环:       定点成环即序列中的Cys按照设计要求形成二硫键,反应过程相对复杂。在 固相合成多肽之前,需要提前设计几对二硫键形成的顺序和方法路线,选择不同的侧链 巯基保护基,利用其性质差异,分步氧化形成两对或多对二硫键。       通常采用的巯基保护 基有trt, Acm, Mmt, tBu, Bzl, Mob, Tmob等多种基团。

    Definition

    Cocaine- and amphetamine- regulated transcript (CART) peptides, derived from proCART polypeptide in humans are neuropeptides expressed in the brain1. They mainly serve as inhibitors of food intake1.

    Discovery

    CART was first purified by gel filtration and sequenced in 1980 from rat hypothalamus2.

    Classification

    CART is a neuropeptide family member2.

    Structural Characteristics

    CART gene encodes a peptide of either 129 or 116 amino acid residues in rat whereas only the short form exists in humans. The predicted signal sequence is 27 amino acid residues resulting in a precursor of 102 or 89 residues3. The C-terminal end of CART, consisting of 48 amino acid residues and 3 disulphide bonds, is thought to constitute a biologically active part of the molecule.  Various CART peptides can be generated from the precursor: CARTs (55-102), (85-102), (55-76) and (62-76)3.  CART (55-102) contains three disulphide bridges that are required for its function4.                                                                    

    Mode of action

    The mode of action of CART peptides has not been fully established. Several studies have observed that they may function through CART receptors in turn activating down stream signaling pathways5.

    Functions

    CART is distributed in the central nervous system and periphery and has many physiological roles.  It elicits similar behavior as cocaine.  CART has been shown to have variety of effects on dopamine6.  It increases blood pressure, has variety of behavioral effects and influences nociception6.  In the hypothalamus CART mainly regulates energy homeostasis6.  CART is also an endogenous inhibitor of food intake6.  CART peptides are also important in anxiety, pain, arousal, startle response, regulation of calcium channels, and neuroendocrine hormone secretion5.

    References

    1.     Thim L, Kristensen P, Larsen PJ, Wulff BS (1998). CART, a new anorectic peptide. Int J Biochem Cell Biol, 30(12), 1281-4.

    2.     Spiess J and Vale W (1980). Multiple forms of somatostatin-like activity in rat hypothalamus. Biochemistry 19, 2861–66.

    3.     Dylag T, Kotlinska J, Rafalski P, Pachuta A, Silberring J (2006). The activity of CART peptide fragments. Peptides, 27(8), 1926-33.

    4.     Murphy KG (2005). Dissecting the role of cocaine and amphetamine-regulated transcript (CART) in the control of appetite. Briefing in Functional Genomics and proteomic, 4 (2),  95–111.

    5.     Rogge G, Jones D, Hubert GW, Lin Y & Kuhar MJ (2008). CART peptides: regulators of body weight, reward and other functions. Nature Reviews Neuroscience, 9, 747-758.

    6.      Vicentic A, Jones DC (2007). The CART (cocaine- and amphetamine-regulated transcript) system in appetite and drug addiction. J Pharmacol Exp Ther., 320(2), 499-506.

  • P.D.Lambert et al., Synapse, 29, 293 (1998);http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=9661247

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