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胰泌素(Secretin)的定义

促胰液素是一种由27个氨基酸组成的肽类激素，当胃内出现酸性内容物时，它会从十二指肠的S细胞中释放出来。促胰液素可增加胰腺腺泡细胞分泌物的体积和碳酸氢盐含量【1】。

Secretin is a peptide hormone composed of 27 amino acids, which is released from S cells of the duodenum in response to the presence of acidic contents in the stomach. Secretin increases the volume and bicarbonate content of secretions from pancreatic acinar cells 【1】.

胰泌素(Secretin)相关肽

胰泌素以激素原前体的形式合成，通过去除信号肽以及氨基和羧基端延伸部分，经蛋白酶解加工生成一条由27个氨基酸组成的肽。成熟肽的序列与胰高血糖素、血管活性肠肽和胃抑制肽的序列相关。

Secretin is synthesized as a preprohormone, which is  proteolytically processed to yield a single 27-amino acid peptide by removal of the signal peptide plus amino and carboxy-terminal extensions. The sequence of the mature peptide is related to that of glucagon, vasoactive intestinal peptide and gastric inhibitory peptide .

胰泌素(Secretin)的发现

1902年，威廉·贝利斯（William Bayliss）和欧内斯特·斯塔林（Ernest Starling）确定，一种由肠壁分泌的物质在通过血液运输后，会刺激胰腺。他们将这种肠壁分泌物命名为促胰液素【2】。

In 1902, William Bayliss and Ernest Starling determined that a substance secreted by the intestinal lining stimulates the pancreas after being transported via the bloodstream. They named this intestinal secretion secretin【2】.

胰泌素(Secretin)的结构特征

通过体内生物测定法，已从猪肠提取物中分离出三种羧基末端（COOH）延伸形式的分泌素。这三种羧基末端延伸肽对应于前分泌素原翻译后加工过程中的顺序步骤，这些步骤最终产生羧基末端酰胺化形式。从前分泌素原中切割信号肽和氨基末端（NH2）侧翼肽，会产生一种中间形式，该形式由延伸了酰胺化区域（Gly-Lys-Arg-）的分泌素和羧基末端侧翼肽组成；这种由71个氨基酸组成的中间形式已从猪肠中纯化出来，并显示出生物活性。加工过程中的下一步可能涉及一种胰蛋白酶样肽酶，该酶特异性作用于成对的碱性残基，在酰胺化区域的羧基侧进行切割，产生分泌素-Gly-Lys-Arg。然后，羧肽酶会去除精氨酸和赖氨酸残基，得到分泌素-Gly。这两种延伸形式也已从猪肠中纯化出来，且据报道前者具有生物活性。在最后一步中，肽酰胺单胺加氧酶会产生羧基末端带有缬氨酸酰胺的分泌素，这是首次分离和测序的分子形式。这些加工事件与其他酰胺化肽的加工事件相似，很可能是所有哺乳动物分泌素加工过程中的步骤。

Three COOH-terminally extended forms of secretin have been isolated from porcine intestinal extracts using an in vivo bioassay. These three COOH-terminally extended peptides correspond to sequential steps in the post-translational processing of preprosecretin that ultimately produce the COOH-terminal amidated form. Cleavage of the signal peptide and an NH2-terminal flanking peptide from preprosecretin produces an intermediate form consisting of secretin extended by an amidation region (Gly-Lys-Arg-) and the COOH-terminal flanking peptide; this 71-amino acid form has been purified from porcine intestine and shown to be bioactive. The next step in processing probably involves a trypsin-like peptidase, specific for pairs of basic residues that cleaves at the COOH side of the amidation region and yields secretin-Gly-Lys-Arg. A carboxypeptidase then removes the arginine and lysine residues to give secretin-Gly. Both of these extended forms have also been purified from porcine intestine, and the former is reported to be bioactive. In a final step, peptide amide monoamine oxygenase then would produce secretin with a COOH-terminal valine-amide, the molecular form that was first isolated and sequenced. These processing events are similar to those seen for other amidated peptides and are likely to be the steps for processing all mammalian secretins.

此外，可能存在另一种胰泌素加工途径；分离出一种NH2端延伸且酰胺化的胰泌素形式表明，上述步骤可能发生在NH2端侧翼区域切割之前【3】。

In addition, an alternative pathway for secretin processing may exist; isolation of an NH2-terminally extended, amidated form of secretin suggests that the steps described above may occur before cleavage of the NH2-terminal flanking region 【3】.

胰泌素(Secretin)的作用机制

促胰液素的活性是通过与人类促胰液素受体（hSCTR）相互作用介导的，hSCTR是一种细胞表面G蛋白偶联受体，对促胰液素表现出纳摩尔级的亲和力。hSCTR是G蛋白偶联受体II类家族的成员，该家族还包括血管活性肠肽（VIP）和垂体腺苷酸环化酶激活肽（PACAP）。该家族的受体在结构上相关，具有序列同源性，并且均由肽配体在生理上激活。主要地，hSCTR的刺激会导致cAMP水平升高，同时还会独立激活胰腺上皮细胞中的其他Ca2+信号通路。在生理上，激动剂与hSCTR结合会强烈刺激电解质（Cl–、HCO3–、K+和Na+）和水的移动，以及胰腺和胆管上皮细胞中的酶分泌【4】。

Secretin's actions are mediated via interaction with the human secretin receptor (hSCTR), a cell surface, GS-coupled receptor, for which it exhibits nanomolar affinity. The hSCTR is a member of the class II G protein–coupled receptor family, which includes vasoactive intestinal peptide (VIP) and pituitary adenylate cyclase–activating polypeptide (PACAP). Receptors of this family are structurally related, show sequence homology, and are all physiologically activated by peptide ligands. Primarily, hSCTR stimulation leads to elevations in cAMP, although independent activation of alternative Ca2+ signaling pathways in the pancreatic epithelium. Physiologically, agonist binding to the hSCTR results in potent stimulation of electrolyte (Cl–, HCO3–, K+, and Na+) and water movement, and enzymatic secretion in the pancreatic and bile duct epithelium【4】.

胰泌素(Secretin)的功能

Secretin stimulates:

a.     The pancreas to emit digestive fluids that are rich in bicarbonate which neutralizes the acidity of the intestines,

b.     The stomach to produce pepsin (an enzyme that aids digestion of protein), and

c.     The liver to produce bile.

The physiological role of the duodenal peptide secretin is as a potent stimulant of electrolyte and water movement in pancreatic and biliary epithelium.

分泌素受体存在于人体肺部，用人体分泌素激活这些受体可强烈刺激支气管上皮细胞以浓度依赖的方式排出氯离子（Cl–），并促进支气管舒张【4】。在大鼠小脑中，分泌素作为逆行信使促进γ-氨基丁酸（GABA）的传递，表明其可调节运动和其他功能。最新数据有力支持了分泌素的神经肽作用。分泌素来源于猪的十二指肠，纯化的猪分泌素（费灵实验室，纽约州萨福恩）于1981年获得美国食品药品监督管理局（FDA）批准，用于单次剂量诊断胃肠道疾病。1998年，ChiRhoClin（马里兰州银泉）合成并生产了纯人分泌素。人分泌素和猪分泌素在人体外分泌胰腺中的动力学和药理作用相当【1】。

Secretin receptors are present in human lung and activation of these receptors with human secretin potently stimulates concentration-dependent Cl– efflux from bronchial epithelial cells and bronchorelaxation 【4】. In the rat cerebellum, secretin functions as a retrograde messenger to facilitate GABA transmission, indicating that it can modulate motor and other functions. Recent data support strongly the neuropeptide role of secretin. Secretin is derived from the duodenum of pigs, and the purified porcine secretin (Ferring Laboratories, Suffern, N.Y.) was approved by the Food and Drug Administration (FDA) in 1981 for single-dose use in the diagnosis of gastrointestinal disorders. Pure human secretin was synthesized and manufactured in 1998 by ChiRhoClin (Silver Spring, Md.). The human and porcine forms of secretin have equivalent kinetics and pharmacologic effects on the exocrine pancreas in humans 【1】.

胰泌素(Secretin)的相关文献

1.     Sandler AD, Sutton KA, DeWeese J, Girardi MA, Sheppard V, Bodfish JW (1999). Lack of Benefit of a Single Dose of Synthetic Human Secretin in the Treatment of Autism and Pervasive Developmental Disorder. NEJM., 341:1801-1806.

2.     Bayliss W, Starling EH (1902). "The mechanism of pancreatic secretion". J. Physiol, 28: 325–353.

3.     Solomon TE, Walsh JH, Bussjaeger L, Zong Y, Hamilton JW, Ho FJ, Lee TD, Reeve JR Jr (1999). COOH-terminally extended secretins are potent stimulants of pancreatic secretion. Am J Physiol., 276:808-816.

4.     Davis RJ, Page KJ, Dos Santos Cruz GJ, Harmer DW, Munday PW, Williams SJ, Picot J, Evans TJ, Sheldrick RL, Coleman RA, Clark KL (2004). Expression and Functions of the Duodenal Peptide Secretin and its Receptor in Human Lung. Am J Respir Cell Mol Biol., 31(3):302-308.

多肽H2N-Tyr-His-Ser-Asp-Gly-Thr-Phe-Thr-Ser-Glu-Leu-Ser-Arg-Leu-Arg-Asp-Ser-Ala-Arg-Leu-Gln-Arg-Leu-Leu-Glu-Gly-Leu-Val-NH2的合成步骤：

1、合成MBHA树脂：取若干克的MBHA树脂（如初始取代度为0.5mmol/g）和1倍树脂摩尔量的Fmoc-Linker-OH加入到反应器中，加入DMF，搅拌使氨基酸完全溶解。再加入树脂2倍量的DIEPA，搅拌混合均匀。再加入树脂0.95倍量的HBTU，搅拌混合均匀。反应3-4小时后，用DMF洗涤3次。用2倍树脂体积的10%乙酸酐/DMF 进行封端30分钟。然后再用DMF洗涤3次，甲醇洗涤2次，DCM洗涤2次，再用甲醇洗涤2次。真空干燥12小时以上，得到干燥的树脂{Fmoc-Linker-MHBA Resin}，测定取代度。这里测得取代度为 0.3mmol/g。结构如下图：

2、脱Fmoc：取1.66g的上述树脂，用DCM或DMF溶胀20分钟。用DMF洗涤2遍。加3倍树脂体积的20%Pip/DMF溶液，鼓氮气30分钟，然后2倍树脂体积的DMF 洗涤5次。得到 H2N-Linker-MBHA Resin 。（此步骤脱除Fmoc基团，茚三酮检测为蓝色，Pip为哌啶）。结构图如下：

3、缩合：取1.49mmol Fmoc-Val-OH 氨基酸，加入到上述树脂里，加适当DMF溶解氨基酸，再依次加入2.99mmol DIPEA，1.42mmol HBTU。反应30分钟后，取小样洗涤，茚三酮检测为无色。用2倍树脂体积的DMF 洗涤3次树脂。（洗涤树脂，去掉残留溶剂，为下一步反应做准备）。得到Fmoc-Val-Linker-MBHA Resin。氨基酸：DIPEA：HBTU：树脂=3：6：2.85：1（摩尔比）。结构图如下：

4、依次循环步骤二、步骤三，依次得到

H2N-Val-Linker-MBHA Resin

Fmoc-Leu-Val-Linker-MBHA Resin

H2N-Leu-Val-Linker-MBHA Resin

Fmoc-Gly-Leu-Val-Linker-MBHA Resin

H2N-Gly-Leu-Val-Linker-MBHA Resin

Fmoc-Glu(OtBu)-Gly-Leu-Val-Linker-MBHA Resin

H2N-Glu(OtBu)-Gly-Leu-Val-Linker-MBHA Resin

Fmoc-Leu-Glu(OtBu)-Gly-Leu-Val-Linker-MBHA Resin

H2N-Leu-Glu(OtBu)-Gly-Leu-Val-Linker-MBHA Resin

Fmoc-Leu-Leu-Glu(OtBu)-Gly-Leu-Val-Linker-MBHA Resin

H2N-Leu-Leu-Glu(OtBu)-Gly-Leu-Val-Linker-MBHA Resin

Fmoc-Arg(Pbf)-Leu-Leu-Glu(OtBu)-Gly-Leu-Val-Linker-MBHA Resin

H2N-Arg(Pbf)-Leu-Leu-Glu(OtBu)-Gly-Leu-Val-Linker-MBHA Resin

Fmoc-Gln(Trt)-Arg(Pbf)-Leu-Leu-Glu(OtBu)-Gly-Leu-Val-Linker-MBHA Resin

H2N-Gln(Trt)-Arg(Pbf)-Leu-Leu-Glu(OtBu)-Gly-Leu-Val-Linker-MBHA Resin

Fmoc-Leu-Gln(Trt)-Arg(Pbf)-Leu-Leu-Glu(OtBu)-Gly-Leu-Val-Linker-MBHA Resin

H2N-Leu-Gln(Trt)-Arg(Pbf)-Leu-Leu-Glu(OtBu)-Gly-Leu-Val-Linker-MBHA Resin

Fmoc-Arg(Pbf)-Leu-Gln(Trt)-Arg(Pbf)-Leu-Leu-Glu(OtBu)-Gly-Leu-Val-Linker-MBHA Resin

H2N-Arg(Pbf)-Leu-Gln(Trt)-Arg(Pbf)-Leu-Leu-Glu(OtBu)-Gly-Leu-Val-Linker-MBHA Resin

Fmoc-Ala-Arg(Pbf)-Leu-Gln(Trt)-Arg(Pbf)-Leu-Leu-Glu(OtBu)-Gly-Leu-Val-Linker-MBHA Resin

H2N-Ala-Arg(Pbf)-Leu-Gln(Trt)-Arg(Pbf)-Leu-Leu-Glu(OtBu)-Gly-Leu-Val-Linker-MBHA Resin

Fmoc-Ser(tBu)-Ala-Arg(Pbf)-Leu-Gln(Trt)-Arg(Pbf)-Leu-Leu-Glu(OtBu)-Gly-Leu-Val-Linker-MBHA Resin

H2N-Ser(tBu)-Ala-Arg(Pbf)-Leu-Gln(Trt)-Arg(Pbf)-Leu-Leu-Glu(OtBu)-Gly-Leu-Val-Linker-MBHA Resin

Fmoc-Asp(OtBu)-Ser(tBu)-Ala-Arg(Pbf)-Leu-Gln(Trt)-Arg(Pbf)-Leu-Leu-Glu(OtBu)-Gly-Leu-Val-Linker-MBHA Resin

H2N-Asp(OtBu)-Ser(tBu)-Ala-Arg(Pbf)-Leu-Gln(Trt)-Arg(Pbf)-Leu-Leu-Glu(OtBu)-Gly-Leu-Val-Linker-MBHA Resin

Fmoc-Arg(Pbf)-Asp(OtBu)-Ser(tBu)-Ala-Arg(Pbf)-Leu-Gln(Trt)-Arg(Pbf)-Leu-Leu-Glu(OtBu)-Gly-Leu-Val-Linker-MBHA Resin

H2N-Arg(Pbf)-Asp(OtBu)-Ser(tBu)-Ala-Arg(Pbf)-Leu-Gln(Trt)-Arg(Pbf)-Leu-Leu-Glu(OtBu)-Gly-Leu-Val-Linker-MBHA Resin

Fmoc-Leu-Arg(Pbf)-Asp(OtBu)-Ser(tBu)-Ala-Arg(Pbf)-Leu-Gln(Trt)-Arg(Pbf)-Leu-Leu-Glu(OtBu)-Gly-Leu-Val-Linker-MBHA Resin

H2N-Leu-Arg(Pbf)-Asp(OtBu)-Ser(tBu)-Ala-Arg(Pbf)-Leu-Gln(Trt)-Arg(Pbf)-Leu-Leu-Glu(OtBu)-Gly-Leu-Val-Linker-MBHA Resin

Fmoc-Arg(Pbf)-Leu-Arg(Pbf)-Asp(OtBu)-Ser(tBu)-Ala-Arg(Pbf)-Leu-Gln(Trt)-Arg(Pbf)-Leu-Leu-Glu(OtBu)-Gly-Leu-Val-Linker-MBHA Resin

H2N-Arg(Pbf)-Leu-Arg(Pbf)-Asp(OtBu)-Ser(tBu)-Ala-Arg(Pbf)-Leu-Gln(Trt)-Arg(Pbf)-Leu-Leu-Glu(OtBu)-Gly-Leu-Val-Linker-MBHA Resin

Fmoc-Ser(tBu)-Arg(Pbf)-Leu-Arg(Pbf)-Asp(OtBu)-Ser(tBu)-Ala-Arg(Pbf)-Leu-Gln(Trt)-Arg(Pbf)-Leu-Leu-Glu(OtBu)-Gly-Leu-Val-Linker-MBHA Resin

H2N-Ser(tBu)-Arg(Pbf)-Leu-Arg(Pbf)-Asp(OtBu)-Ser(tBu)-Ala-Arg(Pbf)-Leu-Gln(Trt)-Arg(Pbf)-Leu-Leu-Glu(OtBu)-Gly-Leu-Val-Linker-MBHA Resin

Fmoc-Leu-Ser(tBu)-Arg(Pbf)-Leu-Arg(Pbf)-Asp(OtBu)-Ser(tBu)-Ala-Arg(Pbf)-Leu-Gln(Trt)-Arg(Pbf)-Leu-Leu-Glu(OtBu)-Gly-Leu-Val-Linker-MBHA Resin

H2N-Leu-Ser(tBu)-Arg(Pbf)-Leu-Arg(Pbf)-Asp(OtBu)-Ser(tBu)-Ala-Arg(Pbf)-Leu-Gln(Trt)-Arg(Pbf)-Leu-Leu-Glu(OtBu)-Gly-Leu-Val-Linker-MBHA Resin

Fmoc-Glu(OtBu)-Leu-Ser(tBu)-Arg(Pbf)-Leu-Arg(Pbf)-Asp(OtBu)-Ser(tBu)-Ala-Arg(Pbf)-Leu-Gln(Trt)-Arg(Pbf)-Leu-Leu-Glu(OtBu)-Gly-Leu-Val-Linker-MBHA Resin

H2N-Glu(OtBu)-Leu-Ser(tBu)-Arg(Pbf)-Leu-Arg(Pbf)-Asp(OtBu)-Ser(tBu)-Ala-Arg(Pbf)-Leu-Gln(Trt)-Arg(Pbf)-Leu-Leu-Glu(OtBu)-Gly-Leu-Val-Linker-MBHA Resin

Fmoc-Ser(tBu)-Glu(OtBu)-Leu-Ser(tBu)-Arg(Pbf)-Leu-Arg(Pbf)-Asp(OtBu)-Ser(tBu)-Ala-Arg(Pbf)-Leu-Gln(Trt)-Arg(Pbf)-Leu-Leu-Glu(OtBu)-Gly-Leu-Val-Linker-MBHA Resin

H2N-Ser(tBu)-Glu(OtBu)-Leu-Ser(tBu)-Arg(Pbf)-Leu-Arg(Pbf)-Asp(OtBu)-Ser(tBu)-Ala-Arg(Pbf)-Leu-Gln(Trt)-Arg(Pbf)-Leu-Leu-Glu(OtBu)-Gly-Leu-Val-Linker-MBHA Resin

Fmoc-Thr(tBu)-Ser(tBu)-Glu(OtBu)-Leu-Ser(tBu)-Arg(Pbf)-Leu-Arg(Pbf)-Asp(OtBu)-Ser(tBu)-Ala-Arg(Pbf)-Leu-Gln(Trt)-Arg(Pbf)-Leu-Leu-Glu(OtBu)-Gly-Leu-Val-Linker-MBHA Resin

H2N-Thr(tBu)-Ser(tBu)-Glu(OtBu)-Leu-Ser(tBu)-Arg(Pbf)-Leu-Arg(Pbf)-Asp(OtBu)-Ser(tBu)-Ala-Arg(Pbf)-Leu-Gln(Trt)-Arg(Pbf)-Leu-Leu-Glu(OtBu)-Gly-Leu-Val-Linker-MBHA Resin

Fmoc-Phe-Thr(tBu)-Ser(tBu)-Glu(OtBu)-Leu-Ser(tBu)-Arg(Pbf)-Leu-Arg(Pbf)-Asp(OtBu)-Ser(tBu)-Ala-Arg(Pbf)-Leu-Gln(Trt)-Arg(Pbf)-Leu-Leu-Glu(OtBu)-Gly-Leu-Val-Linker-MBHA Resin

H2N-Phe-Thr(tBu)-Ser(tBu)-Glu(OtBu)-Leu-Ser(tBu)-Arg(Pbf)-Leu-Arg(Pbf)-Asp(OtBu)-Ser(tBu)-Ala-Arg(Pbf)-Leu-Gln(Trt)-Arg(Pbf)-Leu-Leu-Glu(OtBu)-Gly-Leu-Val-Linker-MBHA Resin

Fmoc-Thr(tBu)-Phe-Thr(tBu)-Ser(tBu)-Glu(OtBu)-Leu-Ser(tBu)-Arg(Pbf)-Leu-Arg(Pbf)-Asp(OtBu)-Ser(tBu)-Ala-Arg(Pbf)-Leu-Gln(Trt)-Arg(Pbf)-Leu-Leu-Glu(OtBu)-Gly-Leu-Val-Linker-MBHA Resin

H2N-Thr(tBu)-Phe-Thr(tBu)-Ser(tBu)-Glu(OtBu)-Leu-Ser(tBu)-Arg(Pbf)-Leu-Arg(Pbf)-Asp(OtBu)-Ser(tBu)-Ala-Arg(Pbf)-Leu-Gln(Trt)-Arg(Pbf)-Leu-Leu-Glu(OtBu)-Gly-Leu-Val-Linker-MBHA Resin

Fmoc-Gly-Thr(tBu)-Phe-Thr(tBu)-Ser(tBu)-Glu(OtBu)-Leu-Ser(tBu)-Arg(Pbf)-Leu-Arg(Pbf)-Asp(OtBu)-Ser(tBu)-Ala-Arg(Pbf)-Leu-Gln(Trt)-Arg(Pbf)-Leu-Leu-Glu(OtBu)-Gly-Leu-Val-Linker-MBHA Resin

H2N-Gly-Thr(tBu)-Phe-Thr(tBu)-Ser(tBu)-Glu(OtBu)-Leu-Ser(tBu)-Arg(Pbf)-Leu-Arg(Pbf)-Asp(OtBu)-Ser(tBu)-Ala-Arg(Pbf)-Leu-Gln(Trt)-Arg(Pbf)-Leu-Leu-Glu(OtBu)-Gly-Leu-Val-Linker-MBHA Resin

Fmoc-Asp(OtBu)-Gly-Thr(tBu)-Phe-Thr(tBu)-Ser(tBu)-Glu(OtBu)-Leu-Ser(tBu)-Arg(Pbf)-Leu-Arg(Pbf)-Asp(OtBu)-Ser(tBu)-Ala-Arg(Pbf)-Leu-Gln(Trt)-Arg(Pbf)-Leu-Leu-Glu(OtBu)-Gly-Leu-Val-Linker-MBHA Resin

H2N-Asp(OtBu)-Gly-Thr(tBu)-Phe-Thr(tBu)-Ser(tBu)-Glu(OtBu)-Leu-Ser(tBu)-Arg(Pbf)-Leu-Arg(Pbf)-Asp(OtBu)-Ser(tBu)-Ala-Arg(Pbf)-Leu-Gln(Trt)-Arg(Pbf)-Leu-Leu-Glu(OtBu)-Gly-Leu-Val-Linker-MBHA Resin

Fmoc-Ser(tBu)-Asp(OtBu)-Gly-Thr(tBu)-Phe-Thr(tBu)-Ser(tBu)-Glu(OtBu)-Leu-Ser(tBu)-Arg(Pbf)-Leu-Arg(Pbf)-Asp(OtBu)-Ser(tBu)-Ala-Arg(Pbf)-Leu-Gln(Trt)-Arg(Pbf)-Leu-Leu-Glu(OtBu)-Gly-Leu-Val-Linker-MBHA Resin

H2N-Ser(tBu)-Asp(OtBu)-Gly-Thr(tBu)-Phe-Thr(tBu)-Ser(tBu)-Glu(OtBu)-Leu-Ser(tBu)-Arg(Pbf)-Leu-Arg(Pbf)-Asp(OtBu)-Ser(tBu)-Ala-Arg(Pbf)-Leu-Gln(Trt)-Arg(Pbf)-Leu-Leu-Glu(OtBu)-Gly-Leu-Val-Linker-MBHA Resin

Fmoc-His(Trt)-Ser(tBu)-Asp(OtBu)-Gly-Thr(tBu)-Phe-Thr(tBu)-Ser(tBu)-Glu(OtBu)-Leu-Ser(tBu)-Arg(Pbf)-Leu-Arg(Pbf)-Asp(OtBu)-Ser(tBu)-Ala-Arg(Pbf)-Leu-Gln(Trt)-Arg(Pbf)-Leu-Leu-Glu(OtBu)-Gly-Leu-Val-Linker-MBHA Resin

H2N-His(Trt)-Ser(tBu)-Asp(OtBu)-Gly-Thr(tBu)-Phe-Thr(tBu)-Ser(tBu)-Glu(OtBu)-Leu-Ser(tBu)-Arg(Pbf)-Leu-Arg(Pbf)-Asp(OtBu)-Ser(tBu)-Ala-Arg(Pbf)-Leu-Gln(Trt)-Arg(Pbf)-Leu-Leu-Glu(OtBu)-Gly-Leu-Val-Linker-MBHA Resin

Fmoc-Tyr(tBu)-His(Trt)-Ser(tBu)-Asp(OtBu)-Gly-Thr(tBu)-Phe-Thr(tBu)-Ser(tBu)-Glu(OtBu)-Leu-Ser(tBu)-Arg(Pbf)-Leu-Arg(Pbf)-Asp(OtBu)-Ser(tBu)-Ala-Arg(Pbf)-Leu-Gln(Trt)-Arg(Pbf)-Leu-Leu-Glu(OtBu)-Gly-Leu-Val-Linker-MBHA Resin

以上中间结构，均可在专肽生物多肽计算器-多肽结构计算器中，一键画出。

最后再经过步骤二得到 H2N-Tyr(tBu)-His(Trt)-Ser(tBu)-Asp(OtBu)-Gly-Thr(tBu)-Phe-Thr(tBu)-Ser(tBu)-Glu(OtBu)-Leu-Ser(tBu)-Arg(Pbf)-Leu-Arg(Pbf)-Asp(OtBu)-Ser(tBu)-Ala-Arg(Pbf)-Leu-Gln(Trt)-Arg(Pbf)-Leu-Leu-Glu(OtBu)-Gly-Leu-Val-Linker-MBHA Resin，结构如下：

5、切割：6倍树脂体积的切割液（或每1g树脂加8ml左右的切割液），摇床摇晃 2小时，过滤掉树脂，用冰无水乙醚沉淀滤液，并用冰无水乙醚洗涤沉淀物3次，最后将沉淀物放真空干燥釜中，常温干燥24小试，得到粗品H2N-Tyr-His-Ser-Asp-Gly-Thr-Phe-Thr-Ser-Glu-Leu-Ser-Arg-Leu-Arg-Asp-Ser-Ala-Arg-Leu-Gln-Arg-Leu-Leu-Glu-Gly-Leu-Val-NH2。结构图见产品结构图。

切割液选择：1）TFA：H2O=95%：5%

2）TFA：H2O：TIS=95%：2.5%：2.5%

3）三氟乙酸：茴香硫醚：1，2-乙二硫醇：苯酚：水=87.5%：5%：2.5%：2.5%：2.5%

（前两种适合没有容易氧化的氨基酸，例如Trp、Cys、Met。第三种适合几乎所有的序列。）

6、纯化冻干：使用液相色谱纯化，收集目标峰液体，进行冻干，获得蓬松的粉末状固体多肽。不过这时要取小样复测下纯度 是否目标纯度。

7、最后总结：

杭州专肽生物技术有限公司（ALLPEPTIDE https://www.allpeptide.com）主营定制多肽合成业务，提供各类长肽，短肽，环肽，提供各类修饰肽，如：荧光标记修饰（CY3、CY5、CY5.5、CY7、FAM、FITC、Rhodamine B、TAMRA等），功能基团修饰肽（叠氮、炔基、DBCO、DOTA、NOTA等），同位素标记肽（N15、C13），订书肽（Stapled Peptide）,脂肪酸修饰肽（Pal、Myr、Ste），磷酸化修饰肽（P-Ser、P-Thr、P-Tyr），环肽（酰胺键环肽、一对或者多对二硫键环），生物素标记肽，PEG修饰肽，甲基化修饰肽等。

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