看到Amyloid β-Protein，第一反应就是和阿尔茨海默氏病有关，这类研究的相关肽种类已经有接近200种了，包括各种缺失肽，某位置氨基酸被替换的肽段（简称替换肽），局部片段肽，含有Met(O)、Met(O2)等杂质肽，生物素FITC等标记肽，等等。
Amyloid β-Protein的相关序列，我们通常称之为淀粉肽，因为大部分长肽片段的性质比较疏水，在溶液中可能发生聚集沉淀，就像淀粉一样，很难溶解，故称之为淀粉肽。
今天介绍其中一种淀粉肽片段，Amyloid β-Protein (1-40)，
其它写法有β-Amyloid (1-40), Aβ40
CAS号：131438-79-4
单字母：DAEFRHDSGYEVHHQKLVFFAEDVGSNKGAIIGLMVGGVV
三字母：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-Met-Val-Gly-Gly-Val-Val
氨基酸个数：40
分子式：C194H295N53O58S1
平均分子量：4329.8034
精确分子量：4327.1481475
等电点(PI)：6.3
pH=7.0时的净电荷数：-1.42
平均亲水性：-0.1
疏水性值：:0.06
结构如下图：
描述：
Compared to the TFA salt, the HCl salt of amyloid β-protein (1-40) easily forms β-structures in PBS within a few hours at 25°C. β-structure formation is essential for amyloid peptide toxicity.
Amyloid β-peptide (1-40) showed both neurotrophic and neurotoxic effects in dependence on the neuronal age and the concentration of the β-protein. Aβ 1-40 has been used as well as Aβ 1-42 to detect amyloid β-protein multimers in the cerebrospinal fluid of Alzheimer's disease patients. The sequence of this peptide corresponds to the sequence of human, bovine, canine, feline, ovine, guinea pig, and rabbit Aβ40. The inverted sequence can be used as inactive control in experiments employing Aβ 1-40. For detailed descriptions of the preparation of wild-type and mutant Aβ 1-40 monomers and protofibrils please see the paper of Jan, Hartley, and Lashuel.
文献：
1、http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=15998280
2、http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=27000658
3、http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=26919121
4、http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=27665848
5、https://www.ncbi.nlm.nih.gov/pubmed/27608011
6、https://www.ncbi.nlm.nih.gov/pubmed/26632651
