The reactive thioether of Met³? is crucial for the activity of Aβ 1-40 and Aβ 1-42. Due to the replacement of Met by inert Nle, M35Nle Aβ 1-40 was no longer toxic to cultured hippocampal neurons and had little effect on the level of protein carbonyl residues. The Nle peptide showed the same propensity to aggregate, whereas sulfoxide formation hindered the required conformational transition from random coil to β-sheet.

淀粉肽背景：β淀粉樣蛋白（Aβ或Abeta）是從淀粉樣前體蛋白加工而成的含有36–43個氨基酸的多肽。Aβ是與阿爾茲海默病相關(guān)的淀粉樣蛋白斑的成分。已有證據(jù)表明，Aβ是一個多功能肽，具有顯著的非病理性活性。Aβ是阿爾茲海默病患者腦中發(fā)現(xiàn)的沉積物的主要成分。在散發(fā)性阿爾茲海默病患者的腦中，Aβ的水平升高，造成腦血管病變和神經(jīng)毒性。Aβ蛋白是由β和γ分泌酶的連續(xù)作用而產(chǎn)生的。γ分泌酶產(chǎn)生Aβ肽的C末端，在APP的轉(zhuǎn)膜結(jié)構(gòu)域切割，可以產(chǎn)生許多36-43個氨基酸殘基長度的異構(gòu)體，最常見的異構(gòu)體是Aβ40和Aβ42。更長形式的Aβ在內(nèi)質(zhì)網(wǎng)中切割產(chǎn)生，而更短形式的Aβ在反面高爾基網(wǎng)中產(chǎn)生。

structure of Amyloid β-Peptide (1-40) (human)

淀粉樣蛋白肽的 定義淀粉樣蛋白 是絲狀蛋白質(zhì)沉積物，大小從納米到微米不等，并且由肽β鏈的平行或反平行排列形成的聚集的肽β折疊構(gòu)成。

結(jié)構(gòu)特征：使用固態(tài)NMR（SSNMR），與計算能量最小化過程結(jié)合，Tycko和合作者已經(jīng)提出從淀粉狀蛋白肽SS（Aß1-40）的40個殘基的形式形成的淀粉樣蛋白原纖維的結(jié)構(gòu)在pH 7.4和24 o C在靜止條件下。在這種結(jié)構(gòu)中，每個Aß1-40分子在原纖維的核心區(qū)域貢獻(xiàn)一對ß鏈，大約跨越殘基12-24和30-40。這些由回路25-29連接的鏈不是同一張ß-sheet的一部分，但參與同一原絲內(nèi)兩個不同的ß-sheets的形成。不同的Aß分子2、3至少從第9到39位殘基以平行排列和對齊的方式相互堆疊。通過調(diào)用其他實驗約束，例如使用透射電子顯微鏡（TEM）觀察到的原絲直徑和單位質(zhì)量通過掃描透射電子顯微鏡（STEM）1、2測得的長度表明，單個原絲是由四個ß片組成的，它們之間的距離約為10Å。

作用模式：阿爾茨海默氏?。ˋD）是淀粉樣蛋白絲狀沉積物的結(jié)果，淀粉狀蛋白沉積物在分子水平上定義該疾病，發(fā)生在神經(jīng)周膜，軸突，樹突和神經(jīng)元末端，如神經(jīng)原纖維纏結(jié)（NFT），在細(xì)胞外神經(jīng)纖維中淀粉樣斑塊（APC），以及周圍的血管稱為淀粉樣嗜血性血管病（ACA）。淀粉樣蛋白沉積物顯然發(fā)生在發(fā)展NFT的神經(jīng)元末端區(qū)域。已經(jīng)表明，APC和ACA的主要成分已被證明是4.5kDa的淀粉樣蛋白，最初被稱為“β-蛋白”或“淀粉樣蛋白A4”，我們現(xiàn)在將其稱為“βA4”。

功能：鈣失調(diào)和膜破壞是可溶性淀粉樣蛋白低聚物普遍存在的神經(jīng)毒性機(jī)制：進(jìn)行了一項研究，以研究Ca 2+信號轉(zhuǎn)導(dǎo)可能參與淀粉樣蛋白誘導(dǎo)的細(xì)胞毒性，疾病相關(guān)淀粉樣蛋白（β，病毒，胰島淀粉樣蛋白）的均質(zhì)制劑制備了處于各種聚集狀態(tài)的多肽，聚谷氨酰胺和溶菌酶），并測試了它們對加載fluo-3的SH-SY5Y細(xì)胞的作用。寡聚形式的所有淀粉樣蛋白的應(yīng)用（0.6-6 µg / ml）迅速（約5 s）使細(xì)胞內(nèi)Ca 2+升高，而等量的單體和原纖維則沒有。細(xì)胞內(nèi)Ca 2+耗盡后，Abeta42低聚物引起的Ca 2+信號持續(xù)存在店，和小信號仍留在鈣2 + -游離介質(zhì)，指示從細(xì)胞外和細(xì)胞內(nèi)Ca貢獻(xiàn)2+源。膜對Ca 2+的滲透性增加不能歸因于內(nèi)源性Ca 2+通道的活化，因為反應(yīng)不受強(qiáng)力的Ca 2 +-通道阻滯劑鈷的影響。取而代之的是，觀察到Abeta42和其他低聚物引起陰離子熒光染料的快速細(xì)胞泄漏，這表明膜通透性普遍提高。導(dǎo)致的離子和分子通量失調(diào)可能為許多淀粉樣變性疾病中Ca 2+失調(diào)提供了由低聚物介導(dǎo)的毒性的常見機(jī)制。離子起著至關(guān)重要的作用，因為它們的跨膜濃度梯度很強(qiáng)，并且參與了細(xì)胞功能障礙和死亡。

2型糖尿病中的胰島淀粉樣蛋白和毒性低聚物假說： 2型糖尿?。═2DM）的特征是胰島素抵抗，胰島素分泌缺陷，β細(xì)胞量減少，β細(xì)胞凋亡增加和胰島淀粉樣蛋白。胰島淀粉樣蛋白源自胰島淀粉樣蛋白多肽（IAPP，胰島淀粉樣多肽），該蛋白是通過胰β細(xì)胞與胰島素共表達(dá)和共分泌的蛋白。與其他淀粉樣蛋白一樣，IAPP具有形成膜滲透性毒性低聚物的傾向。越來越多的證據(jù)表明，這些有毒的寡聚體而不是這些蛋白質(zhì)的細(xì)胞外淀粉樣蛋白形式，是導(dǎo)致神經(jīng)退行性疾病中神經(jīng)元丟失的原因。有人提出，胞內(nèi)IAPP寡聚物的形成可能會導(dǎo)致T2DM 6中的β細(xì)胞丟失。

多肽H2N-Asp-Ala-Glu-Phe-Arg-His-Asp-Ser-Gly-Tyr-Glu-Val-His-His-Gln-Lys-Leu-Val-Phe-Phe-Ala-Glu-Asp-Val-Gly-Ser-Asn-Lys-Gly-Ala-Ile-Ile-Gly-Leu-Nle-Val-Gly-Gly-Val-Val-COOH的合成步驟：

1、合成CTC樹脂：稱取2.74g CTC Resin（如初始取代度約為0.95mmol/g）和3.12mmol Fmoc-Val-OH于反應(yīng)器中，加入適量DCM溶解氨基酸（需要注意，此時CTC樹脂體積會增大好幾倍，避免DCM溶液過少），再加入7.81mmol DIPEA（Mw：129.1,d：0.740g/ml），反應(yīng)2-3小時后，可不抽濾溶液，直接加入1ml的HPLC級甲醇，封端半小時。依次用DMF洗滌2次，甲醇洗滌1次，DCM洗滌一次，甲醇洗滌一次，DCM洗滌一次，DMF洗滌2次（這里使用甲醇和DCM交替洗滌，是為了更好地去除其他溶質(zhì)，有利于后續(xù)反應(yīng)）。得到  Fmoc-Val-CTC Resin。結(jié)構(gòu)圖如下：

2、脫Fmoc：加3倍樹脂體積的20%Pip/DMF溶液，鼓氮?dú)?0分鐘，然后2倍樹脂體積的DMF 洗滌5次。得到 H2N-Val-CTC Resin 。（此步驟脫除Fmoc基團(tuán)，茚三酮檢測為藍(lán)色，Pip為哌啶）。結(jié)構(gòu)圖如下：

3、縮合：取7.81mmol Fmoc-Val-OH 氨基酸，加入到上述樹脂里，加適當(dāng)DMF溶解氨基酸，再依次加入15.62mmol DIPEA，7.42mmol HBTU。反應(yīng)30分鐘后，取小樣洗滌，茚三酮檢測為無色。用2倍樹脂體積的DMF 洗滌3次樹脂。（洗滌樹脂，去掉殘留溶劑，為下一步反應(yīng)做準(zhǔn)備）。得到Fmoc-Val-Val-CTC Resin。氨基酸：DIPEA：HBTU：樹脂=3：6：2.85：1（摩爾比）。結(jié)構(gòu)圖如下：

4、依次循環(huán)步驟二、步驟三，依次得到

H2N-Val-Val-CTC Resin

Fmoc-Gly-Val-Val-CTC Resin

H2N-Gly-Val-Val-CTC Resin

Fmoc-Gly-Gly-Val-Val-CTC Resin

H2N-Gly-Gly-Val-Val-CTC Resin

Fmoc-Val-Gly-Gly-Val-Val-CTC Resin

H2N-Val-Gly-Gly-Val-Val-CTC Resin

Fmoc-Nle-Val-Gly-Gly-Val-Val-CTC Resin

H2N-Nle-Val-Gly-Gly-Val-Val-CTC Resin

Fmoc-Leu-Nle-Val-Gly-Gly-Val-Val-CTC Resin

H2N-Leu-Nle-Val-Gly-Gly-Val-Val-CTC Resin

Fmoc-Gly-Leu-Nle-Val-Gly-Gly-Val-Val-CTC Resin

H2N-Gly-Leu-Nle-Val-Gly-Gly-Val-Val-CTC Resin

Fmoc-Ile-Gly-Leu-Nle-Val-Gly-Gly-Val-Val-CTC Resin

H2N-Ile-Gly-Leu-Nle-Val-Gly-Gly-Val-Val-CTC Resin

Fmoc-Ile-Ile-Gly-Leu-Nle-Val-Gly-Gly-Val-Val-CTC Resin

H2N-Ile-Ile-Gly-Leu-Nle-Val-Gly-Gly-Val-Val-CTC Resin

Fmoc-Ala-Ile-Ile-Gly-Leu-Nle-Val-Gly-Gly-Val-Val-CTC Resin

H2N-Ala-Ile-Ile-Gly-Leu-Nle-Val-Gly-Gly-Val-Val-CTC Resin

Fmoc-Gly-Ala-Ile-Ile-Gly-Leu-Nle-Val-Gly-Gly-Val-Val-CTC Resin

H2N-Gly-Ala-Ile-Ile-Gly-Leu-Nle-Val-Gly-Gly-Val-Val-CTC Resin

Fmoc-Lys(Boc)-Gly-Ala-Ile-Ile-Gly-Leu-Nle-Val-Gly-Gly-Val-Val-CTC Resin

H2N-Lys(Boc)-Gly-Ala-Ile-Ile-Gly-Leu-Nle-Val-Gly-Gly-Val-Val-CTC Resin

Fmoc-Asn(Trt)-Lys(Boc)-Gly-Ala-Ile-Ile-Gly-Leu-Nle-Val-Gly-Gly-Val-Val-CTC Resin

H2N-Asn(Trt)-Lys(Boc)-Gly-Ala-Ile-Ile-Gly-Leu-Nle-Val-Gly-Gly-Val-Val-CTC Resin

Fmoc-Ser(tBu)-Asn(Trt)-Lys(Boc)-Gly-Ala-Ile-Ile-Gly-Leu-Nle-Val-Gly-Gly-Val-Val-CTC Resin

H2N-Ser(tBu)-Asn(Trt)-Lys(Boc)-Gly-Ala-Ile-Ile-Gly-Leu-Nle-Val-Gly-Gly-Val-Val-CTC Resin

Fmoc-Gly-Ser(tBu)-Asn(Trt)-Lys(Boc)-Gly-Ala-Ile-Ile-Gly-Leu-Nle-Val-Gly-Gly-Val-Val-CTC Resin

H2N-Gly-Ser(tBu)-Asn(Trt)-Lys(Boc)-Gly-Ala-Ile-Ile-Gly-Leu-Nle-Val-Gly-Gly-Val-Val-CTC Resin

Fmoc-Val-Gly-Ser(tBu)-Asn(Trt)-Lys(Boc)-Gly-Ala-Ile-Ile-Gly-Leu-Nle-Val-Gly-Gly-Val-Val-CTC Resin

H2N-Val-Gly-Ser(tBu)-Asn(Trt)-Lys(Boc)-Gly-Ala-Ile-Ile-Gly-Leu-Nle-Val-Gly-Gly-Val-Val-CTC Resin

Fmoc-Asp(OtBu)-Val-Gly-Ser(tBu)-Asn(Trt)-Lys(Boc)-Gly-Ala-Ile-Ile-Gly-Leu-Nle-Val-Gly-Gly-Val-Val-CTC Resin

H2N-Asp(OtBu)-Val-Gly-Ser(tBu)-Asn(Trt)-Lys(Boc)-Gly-Ala-Ile-Ile-Gly-Leu-Nle-Val-Gly-Gly-Val-Val-CTC Resin

Fmoc-Glu(OtBu)-Asp(OtBu)-Val-Gly-Ser(tBu)-Asn(Trt)-Lys(Boc)-Gly-Ala-Ile-Ile-Gly-Leu-Nle-Val-Gly-Gly-Val-Val-CTC Resin

H2N-Glu(OtBu)-Asp(OtBu)-Val-Gly-Ser(tBu)-Asn(Trt)-Lys(Boc)-Gly-Ala-Ile-Ile-Gly-Leu-Nle-Val-Gly-Gly-Val-Val-CTC Resin

Fmoc-Ala-Glu(OtBu)-Asp(OtBu)-Val-Gly-Ser(tBu)-Asn(Trt)-Lys(Boc)-Gly-Ala-Ile-Ile-Gly-Leu-Nle-Val-Gly-Gly-Val-Val-CTC Resin

H2N-Ala-Glu(OtBu)-Asp(OtBu)-Val-Gly-Ser(tBu)-Asn(Trt)-Lys(Boc)-Gly-Ala-Ile-Ile-Gly-Leu-Nle-Val-Gly-Gly-Val-Val-CTC Resin

Fmoc-Phe-Ala-Glu(OtBu)-Asp(OtBu)-Val-Gly-Ser(tBu)-Asn(Trt)-Lys(Boc)-Gly-Ala-Ile-Ile-Gly-Leu-Nle-Val-Gly-Gly-Val-Val-CTC Resin

H2N-Phe-Ala-Glu(OtBu)-Asp(OtBu)-Val-Gly-Ser(tBu)-Asn(Trt)-Lys(Boc)-Gly-Ala-Ile-Ile-Gly-Leu-Nle-Val-Gly-Gly-Val-Val-CTC Resin

Fmoc-Phe-Phe-Ala-Glu(OtBu)-Asp(OtBu)-Val-Gly-Ser(tBu)-Asn(Trt)-Lys(Boc)-Gly-Ala-Ile-Ile-Gly-Leu-Nle-Val-Gly-Gly-Val-Val-CTC Resin

H2N-Phe-Phe-Ala-Glu(OtBu)-Asp(OtBu)-Val-Gly-Ser(tBu)-Asn(Trt)-Lys(Boc)-Gly-Ala-Ile-Ile-Gly-Leu-Nle-Val-Gly-Gly-Val-Val-CTC Resin

Fmoc-Val-Phe-Phe-Ala-Glu(OtBu)-Asp(OtBu)-Val-Gly-Ser(tBu)-Asn(Trt)-Lys(Boc)-Gly-Ala-Ile-Ile-Gly-Leu-Nle-Val-Gly-Gly-Val-Val-CTC Resin

H2N-Val-Phe-Phe-Ala-Glu(OtBu)-Asp(OtBu)-Val-Gly-Ser(tBu)-Asn(Trt)-Lys(Boc)-Gly-Ala-Ile-Ile-Gly-Leu-Nle-Val-Gly-Gly-Val-Val-CTC Resin

Fmoc-Leu-Val-Phe-Phe-Ala-Glu(OtBu)-Asp(OtBu)-Val-Gly-Ser(tBu)-Asn(Trt)-Lys(Boc)-Gly-Ala-Ile-Ile-Gly-Leu-Nle-Val-Gly-Gly-Val-Val-CTC Resin

H2N-Leu-Val-Phe-Phe-Ala-Glu(OtBu)-Asp(OtBu)-Val-Gly-Ser(tBu)-Asn(Trt)-Lys(Boc)-Gly-Ala-Ile-Ile-Gly-Leu-Nle-Val-Gly-Gly-Val-Val-CTC Resin

Fmoc-Lys(Boc)-Leu-Val-Phe-Phe-Ala-Glu(OtBu)-Asp(OtBu)-Val-Gly-Ser(tBu)-Asn(Trt)-Lys(Boc)-Gly-Ala-Ile-Ile-Gly-Leu-Nle-Val-Gly-Gly-Val-Val-CTC Resin

H2N-Lys(Boc)-Leu-Val-Phe-Phe-Ala-Glu(OtBu)-Asp(OtBu)-Val-Gly-Ser(tBu)-Asn(Trt)-Lys(Boc)-Gly-Ala-Ile-Ile-Gly-Leu-Nle-Val-Gly-Gly-Val-Val-CTC Resin

Fmoc-Gln(Trt)-Lys(Boc)-Leu-Val-Phe-Phe-Ala-Glu(OtBu)-Asp(OtBu)-Val-Gly-Ser(tBu)-Asn(Trt)-Lys(Boc)-Gly-Ala-Ile-Ile-Gly-Leu-Nle-Val-Gly-Gly-Val-Val-CTC Resin

H2N-Gln(Trt)-Lys(Boc)-Leu-Val-Phe-Phe-Ala-Glu(OtBu)-Asp(OtBu)-Val-Gly-Ser(tBu)-Asn(Trt)-Lys(Boc)-Gly-Ala-Ile-Ile-Gly-Leu-Nle-Val-Gly-Gly-Val-Val-CTC Resin

Fmoc-His(Trt)-Gln(Trt)-Lys(Boc)-Leu-Val-Phe-Phe-Ala-Glu(OtBu)-Asp(OtBu)-Val-Gly-Ser(tBu)-Asn(Trt)-Lys(Boc)-Gly-Ala-Ile-Ile-Gly-Leu-Nle-Val-Gly-Gly-Val-Val-CTC Resin

H2N-His(Trt)-Gln(Trt)-Lys(Boc)-Leu-Val-Phe-Phe-Ala-Glu(OtBu)-Asp(OtBu)-Val-Gly-Ser(tBu)-Asn(Trt)-Lys(Boc)-Gly-Ala-Ile-Ile-Gly-Leu-Nle-Val-Gly-Gly-Val-Val-CTC Resin

Fmoc-His(Trt)-His(Trt)-Gln(Trt)-Lys(Boc)-Leu-Val-Phe-Phe-Ala-Glu(OtBu)-Asp(OtBu)-Val-Gly-Ser(tBu)-Asn(Trt)-Lys(Boc)-Gly-Ala-Ile-Ile-Gly-Leu-Nle-Val-Gly-Gly-Val-Val-CTC Resin

H2N-His(Trt)-His(Trt)-Gln(Trt)-Lys(Boc)-Leu-Val-Phe-Phe-Ala-Glu(OtBu)-Asp(OtBu)-Val-Gly-Ser(tBu)-Asn(Trt)-Lys(Boc)-Gly-Ala-Ile-Ile-Gly-Leu-Nle-Val-Gly-Gly-Val-Val-CTC Resin

Fmoc-Val-His(Trt)-His(Trt)-Gln(Trt)-Lys(Boc)-Leu-Val-Phe-Phe-Ala-Glu(OtBu)-Asp(OtBu)-Val-Gly-Ser(tBu)-Asn(Trt)-Lys(Boc)-Gly-Ala-Ile-Ile-Gly-Leu-Nle-Val-Gly-Gly-Val-Val-CTC Resin

H2N-Val-His(Trt)-His(Trt)-Gln(Trt)-Lys(Boc)-Leu-Val-Phe-Phe-Ala-Glu(OtBu)-Asp(OtBu)-Val-Gly-Ser(tBu)-Asn(Trt)-Lys(Boc)-Gly-Ala-Ile-Ile-Gly-Leu-Nle-Val-Gly-Gly-Val-Val-CTC Resin

Fmoc-Glu(OtBu)-Val-His(Trt)-His(Trt)-Gln(Trt)-Lys(Boc)-Leu-Val-Phe-Phe-Ala-Glu(OtBu)-Asp(OtBu)-Val-Gly-Ser(tBu)-Asn(Trt)-Lys(Boc)-Gly-Ala-Ile-Ile-Gly-Leu-Nle-Val-Gly-Gly-Val-Val-CTC Resin

H2N-Glu(OtBu)-Val-His(Trt)-His(Trt)-Gln(Trt)-Lys(Boc)-Leu-Val-Phe-Phe-Ala-Glu(OtBu)-Asp(OtBu)-Val-Gly-Ser(tBu)-Asn(Trt)-Lys(Boc)-Gly-Ala-Ile-Ile-Gly-Leu-Nle-Val-Gly-Gly-Val-Val-CTC Resin

Fmoc-Tyr(tBu)-Glu(OtBu)-Val-His(Trt)-His(Trt)-Gln(Trt)-Lys(Boc)-Leu-Val-Phe-Phe-Ala-Glu(OtBu)-Asp(OtBu)-Val-Gly-Ser(tBu)-Asn(Trt)-Lys(Boc)-Gly-Ala-Ile-Ile-Gly-Leu-Nle-Val-Gly-Gly-Val-Val-CTC Resin

H2N-Tyr(tBu)-Glu(OtBu)-Val-His(Trt)-His(Trt)-Gln(Trt)-Lys(Boc)-Leu-Val-Phe-Phe-Ala-Glu(OtBu)-Asp(OtBu)-Val-Gly-Ser(tBu)-Asn(Trt)-Lys(Boc)-Gly-Ala-Ile-Ile-Gly-Leu-Nle-Val-Gly-Gly-Val-Val-CTC Resin

Fmoc-Gly-Tyr(tBu)-Glu(OtBu)-Val-His(Trt)-His(Trt)-Gln(Trt)-Lys(Boc)-Leu-Val-Phe-Phe-Ala-Glu(OtBu)-Asp(OtBu)-Val-Gly-Ser(tBu)-Asn(Trt)-Lys(Boc)-Gly-Ala-Ile-Ile-Gly-Leu-Nle-Val-Gly-Gly-Val-Val-CTC Resin

H2N-Gly-Tyr(tBu)-Glu(OtBu)-Val-His(Trt)-His(Trt)-Gln(Trt)-Lys(Boc)-Leu-Val-Phe-Phe-Ala-Glu(OtBu)-Asp(OtBu)-Val-Gly-Ser(tBu)-Asn(Trt)-Lys(Boc)-Gly-Ala-Ile-Ile-Gly-Leu-Nle-Val-Gly-Gly-Val-Val-CTC Resin

Fmoc-Ser(tBu)-Gly-Tyr(tBu)-Glu(OtBu)-Val-His(Trt)-His(Trt)-Gln(Trt)-Lys(Boc)-Leu-Val-Phe-Phe-Ala-Glu(OtBu)-Asp(OtBu)-Val-Gly-Ser(tBu)-Asn(Trt)-Lys(Boc)-Gly-Ala-Ile-Ile-Gly-Leu-Nle-Val-Gly-Gly-Val-Val-CTC Resin

H2N-Ser(tBu)-Gly-Tyr(tBu)-Glu(OtBu)-Val-His(Trt)-His(Trt)-Gln(Trt)-Lys(Boc)-Leu-Val-Phe-Phe-Ala-Glu(OtBu)-Asp(OtBu)-Val-Gly-Ser(tBu)-Asn(Trt)-Lys(Boc)-Gly-Ala-Ile-Ile-Gly-Leu-Nle-Val-Gly-Gly-Val-Val-CTC Resin

Fmoc-Asp(OtBu)-Ser(tBu)-Gly-Tyr(tBu)-Glu(OtBu)-Val-His(Trt)-His(Trt)-Gln(Trt)-Lys(Boc)-Leu-Val-Phe-Phe-Ala-Glu(OtBu)-Asp(OtBu)-Val-Gly-Ser(tBu)-Asn(Trt)-Lys(Boc)-Gly-Ala-Ile-Ile-Gly-Leu-Nle-Val-Gly-Gly-Val-Val-CTC Resin

H2N-Asp(OtBu)-Ser(tBu)-Gly-Tyr(tBu)-Glu(OtBu)-Val-His(Trt)-His(Trt)-Gln(Trt)-Lys(Boc)-Leu-Val-Phe-Phe-Ala-Glu(OtBu)-Asp(OtBu)-Val-Gly-Ser(tBu)-Asn(Trt)-Lys(Boc)-Gly-Ala-Ile-Ile-Gly-Leu-Nle-Val-Gly-Gly-Val-Val-CTC Resin

Fmoc-His(Trt)-Asp(OtBu)-Ser(tBu)-Gly-Tyr(tBu)-Glu(OtBu)-Val-His(Trt)-His(Trt)-Gln(Trt)-Lys(Boc)-Leu-Val-Phe-Phe-Ala-Glu(OtBu)-Asp(OtBu)-Val-Gly-Ser(tBu)-Asn(Trt)-Lys(Boc)-Gly-Ala-Ile-Ile-Gly-Leu-Nle-Val-Gly-Gly-Val-Val-CTC Resin

H2N-His(Trt)-Asp(OtBu)-Ser(tBu)-Gly-Tyr(tBu)-Glu(OtBu)-Val-His(Trt)-His(Trt)-Gln(Trt)-Lys(Boc)-Leu-Val-Phe-Phe-Ala-Glu(OtBu)-Asp(OtBu)-Val-Gly-Ser(tBu)-Asn(Trt)-Lys(Boc)-Gly-Ala-Ile-Ile-Gly-Leu-Nle-Val-Gly-Gly-Val-Val-CTC Resin

Fmoc-Arg(Pbf)-His(Trt)-Asp(OtBu)-Ser(tBu)-Gly-Tyr(tBu)-Glu(OtBu)-Val-His(Trt)-His(Trt)-Gln(Trt)-Lys(Boc)-Leu-Val-Phe-Phe-Ala-Glu(OtBu)-Asp(OtBu)-Val-Gly-Ser(tBu)-Asn(Trt)-Lys(Boc)-Gly-Ala-Ile-Ile-Gly-Leu-Nle-Val-Gly-Gly-Val-Val-CTC Resin

H2N-Arg(Pbf)-His(Trt)-Asp(OtBu)-Ser(tBu)-Gly-Tyr(tBu)-Glu(OtBu)-Val-His(Trt)-His(Trt)-Gln(Trt)-Lys(Boc)-Leu-Val-Phe-Phe-Ala-Glu(OtBu)-Asp(OtBu)-Val-Gly-Ser(tBu)-Asn(Trt)-Lys(Boc)-Gly-Ala-Ile-Ile-Gly-Leu-Nle-Val-Gly-Gly-Val-Val-CTC Resin

Fmoc-Phe-Arg(Pbf)-His(Trt)-Asp(OtBu)-Ser(tBu)-Gly-Tyr(tBu)-Glu(OtBu)-Val-His(Trt)-His(Trt)-Gln(Trt)-Lys(Boc)-Leu-Val-Phe-Phe-Ala-Glu(OtBu)-Asp(OtBu)-Val-Gly-Ser(tBu)-Asn(Trt)-Lys(Boc)-Gly-Ala-Ile-Ile-Gly-Leu-Nle-Val-Gly-Gly-Val-Val-CTC Resin

H2N-Phe-Arg(Pbf)-His(Trt)-Asp(OtBu)-Ser(tBu)-Gly-Tyr(tBu)-Glu(OtBu)-Val-His(Trt)-His(Trt)-Gln(Trt)-Lys(Boc)-Leu-Val-Phe-Phe-Ala-Glu(OtBu)-Asp(OtBu)-Val-Gly-Ser(tBu)-Asn(Trt)-Lys(Boc)-Gly-Ala-Ile-Ile-Gly-Leu-Nle-Val-Gly-Gly-Val-Val-CTC Resin

Fmoc-Glu(OtBu)-Phe-Arg(Pbf)-His(Trt)-Asp(OtBu)-Ser(tBu)-Gly-Tyr(tBu)-Glu(OtBu)-Val-His(Trt)-His(Trt)-Gln(Trt)-Lys(Boc)-Leu-Val-Phe-Phe-Ala-Glu(OtBu)-Asp(OtBu)-Val-Gly-Ser(tBu)-Asn(Trt)-Lys(Boc)-Gly-Ala-Ile-Ile-Gly-Leu-Nle-Val-Gly-Gly-Val-Val-CTC Resin

H2N-Glu(OtBu)-Phe-Arg(Pbf)-His(Trt)-Asp(OtBu)-Ser(tBu)-Gly-Tyr(tBu)-Glu(OtBu)-Val-His(Trt)-His(Trt)-Gln(Trt)-Lys(Boc)-Leu-Val-Phe-Phe-Ala-Glu(OtBu)-Asp(OtBu)-Val-Gly-Ser(tBu)-Asn(Trt)-Lys(Boc)-Gly-Ala-Ile-Ile-Gly-Leu-Nle-Val-Gly-Gly-Val-Val-CTC Resin

Fmoc-Ala-Glu(OtBu)-Phe-Arg(Pbf)-His(Trt)-Asp(OtBu)-Ser(tBu)-Gly-Tyr(tBu)-Glu(OtBu)-Val-His(Trt)-His(Trt)-Gln(Trt)-Lys(Boc)-Leu-Val-Phe-Phe-Ala-Glu(OtBu)-Asp(OtBu)-Val-Gly-Ser(tBu)-Asn(Trt)-Lys(Boc)-Gly-Ala-Ile-Ile-Gly-Leu-Nle-Val-Gly-Gly-Val-Val-CTC Resin

H2N-Ala-Glu(OtBu)-Phe-Arg(Pbf)-His(Trt)-Asp(OtBu)-Ser(tBu)-Gly-Tyr(tBu)-Glu(OtBu)-Val-His(Trt)-His(Trt)-Gln(Trt)-Lys(Boc)-Leu-Val-Phe-Phe-Ala-Glu(OtBu)-Asp(OtBu)-Val-Gly-Ser(tBu)-Asn(Trt)-Lys(Boc)-Gly-Ala-Ile-Ile-Gly-Leu-Nle-Val-Gly-Gly-Val-Val-CTC Resin

Fmoc-Asp(OtBu)-Ala-Glu(OtBu)-Phe-Arg(Pbf)-His(Trt)-Asp(OtBu)-Ser(tBu)-Gly-Tyr(tBu)-Glu(OtBu)-Val-His(Trt)-His(Trt)-Gln(Trt)-Lys(Boc)-Leu-Val-Phe-Phe-Ala-Glu(OtBu)-Asp(OtBu)-Val-Gly-Ser(tBu)-Asn(Trt)-Lys(Boc)-Gly-Ala-Ile-Ile-Gly-Leu-Nle-Val-Gly-Gly-Val-Val-CTC Resin

以上中間結(jié)構(gòu)，均可在專肽生物多肽計算器-多肽結(jié)構(gòu)計算器中，一鍵畫出。

最后再經(jīng)過步驟二得到 H2N-Asp(OtBu)-Ala-Glu(OtBu)-Phe-Arg(Pbf)-His(Trt)-Asp(OtBu)-Ser(tBu)-Gly-Tyr(tBu)-Glu(OtBu)-Val-His(Trt)-His(Trt)-Gln(Trt)-Lys(Boc)-Leu-Val-Phe-Phe-Ala-Glu(OtBu)-Asp(OtBu)-Val-Gly-Ser(tBu)-Asn(Trt)-Lys(Boc)-Gly-Ala-Ile-Ile-Gly-Leu-Nle-Val-Gly-Gly-Val-Val-CTC Resin，結(jié)構(gòu)如下：

5、切割：6倍樹脂體積的切割液（或每1g樹脂加8ml左右的切割液），搖床搖晃 2小時，過濾掉樹脂，用冰無水乙醚沉淀濾液，并用冰無水乙醚洗滌沉淀物3次，最后將沉淀物放真空干燥釜中，常溫干燥24小試，得到粗品H2N-Asp-Ala-Glu-Phe-Arg-His-Asp-Ser-Gly-Tyr-Glu-Val-His-His-Gln-Lys-Leu-Val-Phe-Phe-Ala-Glu-Asp-Val-Gly-Ser-Asn-Lys-Gly-Ala-Ile-Ile-Gly-Leu-Nle-Val-Gly-Gly-Val-Val-COOH。結(jié)構(gòu)圖見產(chǎn)品結(jié)構(gòu)圖。

切割液選擇：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%

（前兩種適合沒有容易氧化的氨基酸，例如Trp、Cys、Met。第三種適合幾乎所有的序列。）

6、純化凍干：使用液相色譜純化，收集目標(biāo)峰液體，進(jìn)行凍干，獲得蓬松的粉末狀固體多肽。不過這時要取小樣復(fù)測下純度 是否目標(biāo)純度。

7、最后總結(jié)：

杭州專肽生物技術(shù)有限公司（ALLPEPTIDE http://www.cqhongyadong.com.cn）主營定制多肽合成業(yè)務(wù)，提供各類長肽，短肽，環(huán)肽，提供各類修飾肽，如：熒光標(biāo)記修飾（CY3、CY5、CY5.5、CY7、FAM、FITC、Rhodamine B、TAMRA等），功能基團(tuán)修飾肽（疊氮、炔基、DBCO、DOTA、NOTA等），同位素標(biāo)記肽（N15、C13），訂書肽（Stapled Peptide）,脂肪酸修飾肽（Pal、Myr、Ste），磷酸化修飾肽（P-Ser、P-Thr、P-Tyr），環(huán)肽（酰胺鍵環(huán)肽、一對或者多對二硫鍵環(huán)），生物素標(biāo)記肽，PEG修飾肽，甲基化修飾肽等。

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