编号：142117
CAS号：114547-28-3
单字母：H2N-DSGCFGRRLDRIGSLSGLGCNVLRRY-OH(Disulfide Bridge:C4-C20)
| 编号: | 142117 |
| 中文名称: | BNP(7-32), porcine |
| 英文名: | BNP(7-32), porcine |
| 英文同义词: | BNP (7-32) |
| CAS号: | 114547-28-3 |
| 单字母: | H2N-DSGCFGRRLDRIGSLSGLGCNVLRRY-OH(Disulfide Bridge:C4-C20) |
| 三字母: | H2N-Asp-Ser-Gly-Cys-Phe-Gly-Arg-Arg-Leu-Asp-Arg-Ile-Gly-Ser-Leu-Ser-Gly-Leu-Gly-Cys-Asn-Val-Leu-Arg-Arg-Tyr-OH(Disulfide Bridge:Cys4-Cys20) |
| 氨基酸个数: | 26 |
| 分子式: | C120H198N42O36S2 |
| 平均分子量: | 2869.25 |
| 精确分子量: | 2867.44 |
| 等电点(PI): | 12.68 |
| pH=7.0时的净电荷数: | 6.91 |
| 平均亲水性: | 0.17619047619048 |
| 疏水性值: | -0.25 |
| 外观与性状: | 白色粉末状固体 |
| 消光系数: | 1490 |
| 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 脑钠肽(Brain natriuretic peptide, BNP) |
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
Brain natriuretic peptide (BNP) is a 32 amino acid polypeptide that is secreted by the ventricles of the heart in response to stretching of heart muscles1.
Discovery
BNP was first discovered in porcine brain extracts based on its resemblance to atrial natriuretic peptide (a hormone secreted by mammalian atria) 1.
Classification
BNP belongs to the natriuretic family of peptides that contain three structurally related paracrine factors: Atrial, Brain and C-type natruirectic peptides2. Both atrial and brain natriuretic peptides are secreted in the atria and ventricles of the heart while C-type peptide is secreted in the bone2. BNP is co-secreted along with a 76 amino acid N-terminal fragment (NT-proBNP) which is biologically inactive3.
Structural Characteristics
BNP is a horseshoe-shaped 32 amino acid peptide that is held by a disulphide bridge formed between amino acids 10 and 264. It is produced by cleavage of large precursors- prepro and prohormones4.
Mode of action
BNP activates a transmembrane guanylyl cyclase, natriuretic peptide receptor-A (NPR-A). Activated NPR-A in turn produces the second messenger cGMP that triggers effectors that mediate its cardiac functions5,6.
Functions
BNP similar to ANP decreases systemic vascular resistance and central venous pressure resulting in a decrease in cardiac output and blood volume7. Both BNP and NT-proBNP levels in the blood are used for screening, diagnosis of acute congestive heart failure (CHF) and may be useful to establish prognosis in heart failure, as both markers are typically higher in patients with worse outcome8. The plasma concentrations of both BNP and NT-proBNP are also typically increased in patients with asymptomatic or symptomatic left ventricular dysfunction8.
BNP plays a very important role in prognostication of millions of diabetics9. It has an improtant role in prognostication of heart surgery patients10. It has been shown that combining BNP with other tools like ICG can improve early diagnosis of heart failure and advance prevention strategies11. BNP can be elevated in renal failure12. The BNP test is used as an aid in the diagnosis and assessment of severity of congestive heart failure (also referred to as heart failure)13.
References
1. Tetsuji S, Kenji K, Naoto M and Hisayuki M (1988), A new natriuretic peptide in porcine brain, Nature, 332, 78-81.
2. Potter LR, Yoder AR, Flora DR, Antos LK, Dickey DM (2009), Natruiretic peptides: their structures, receptors, physiologic functions and therapeutic applications, Handb Exp Pharmacol, 191, 341-66.
3. Bibbins-Domingo K, Gupta R, Na B, Wu AH, Schiller NB, Whooley MA (2007). "N-terminal fragment of the prohormone brain-type natriuretic peptide (NT-proBNP), cardiovascular events, and mortality in patients with stable coronary heart disease". JAMA 297 (2): 169–76.
4. Brandt I, Lambeir AM, Ketelsleger JM, Vanderheyden M, Scharpé S and Meest ID, (2006), Dipeptidyl-peptidase IV converts intact B-type natriuretic peptide into its des-SerPro form. Clin. Chem, 52(1): 82-87.
5. David G. Lowe (1992), Human natriuretic peptide receptor-A guanylyl cyclase is self-associated prior to hormone binding, Biochemistry, 31 (43), pp 10421–10425.
6. Jun S, Peter M. S and Harvey R. W, (2005), Differential Effects of cGMP Produced by Soluble and Particulate Guanylyl Cyclase on Mouse Ventricular Myocytes, Experimental Biology and Medicine 230:242-250.
7. Bhalla V, Willis S, Maisel AS (2004). "B-type natriuretic peptide: the level and the drug--partners in the diagnosis of congestive heart failure". Congest Heart Fail 10(1 Suppl 1): 3–27.
8. Atisha D, Bhalla MA, Morrison LK, Felicio L, Clopton P, Gardetto N, Kazanegra R, Chiu A, Maisel AS (2004). "A prospective study in search of an optimal B-natriuretic peptide level to screen patients for cardiac dysfunction". Am. Heart J. 148 (3): 518–23.
9. Bhalla MA, Chiang A, Epshteyn VA, Kazanegra R, Bhalla V, Clopton P, Krishnaswamy P, Morrison LK, Chiu A, Gardetto N, Mudaliar S, Edelman SV, Henry RR, Maisel AS (2004). "Prognostic role of B-type natriuretic peptide levels in patients with type 2 diabetes mellitus". J. Am. Coll. Cardiol. 44 (5): 1047–52.
10. Lee CY, Burnett JC Jr. (2007), Natruiteric peptides and therapeutic applications, Heart Fail Rev, 12 (2), 131-42
11. Castellanos LR, Bhalla V, Isakson S, Daniels LB, Bhalla MA, Lin JP, Clopton P, Gardetto N, Hoshino M, Chiu A, Fitzgerald R, Maisel AS (2009). "B-type natriuretic peptide and impedance cardiography at the time of routine echocardiography predict subsequent heart failure events". J. Card. Fail. 15 (1): 41–7.
12. Bhalla V, Maisel AS (June 2004). "B-type natriuretic peptide. A biomarker for all the right reasons". Ital Heart J 5 (6): 417–20.
13. Fitzgerald RL, Cremo R, Gardetto N, Chiu A, Clopton P, Bhalla V, Maisel AS (2005). "Effect of nesiritide in combination with standard therapy on serum concentrations of natriuretic peptides in patients admitted for decompensated congestive heart failure". Am. Heart J. 150 (3): 471–7.
