beta-Amyloid (1-42) human
[CAS 107761-42-2]

Identification

• Classification: Biochemical >> Peptide
• Name: beta-Amyloid (1-42) human
• Synonyms: (4S)-5-[[(2S)-1-[[(2S)-1-[[(2S)-1-[[(2S)-1-[[(2S)-1-[[2-[[(2S)-1-[[(2S)-1-[[(2S)-1-[[(2S)-1-[[(2S)-1-[[(2S)-5-amino-1-[[(2S)-6-amino-1-[[(2S)-1-[[(2S)-1-[[(2S)-1-[[(2S)-1-[[(2S)-1-[[(2S)-1-[[(2S)-1-[[(2S)-1-[[2-[[(2S)-1-[[(2S)-4-amino-1-[[(2S)-6-amino-1-[[2-[[(2S)-1-[[(2S,3S)-1-[[(2S,3S)-1-[[2-[[(2S)-1-[[(2S)-1-[[(2S)-1-[[2-[[2-[[(2S)-1-[[(2S)-1-[[(2S,3S)-1-[[(1S)-1-carboxyethyl]amino]-3-methyl-1-oxopentan-2-yl]amino]-3-methyl-1-oxobutan-2-yl]amino]-3-methyl-1-oxobutan-2-yl]amino]-2-oxoethyl]amino]-2-oxoethyl]amino]-3-methyl-1-oxobutan-2-yl]amino]-4-methylsulfanyl-1-oxobutan-2-yl]amino]-4-methyl-1-oxopentan-2-yl]amino]-2-oxoethyl]amino]-3-methyl-1-oxopentan-2-yl]amino]-3-methyl-1-oxopentan-2-yl]amino]-1-oxopropan-2-yl]amino]-2-oxoethyl]amino]-1-oxohexan-2-yl]amino]-1,4-dioxobutan-2-yl]amino]-3-hydroxy-1-oxopropan-2-yl]amino]-2-oxoethyl]amino]-3-methyl-1-oxobutan-2-yl]amino]-3-carboxy-1-oxopropan-2-yl]amino]-4-carboxy-1-oxobutan-2-yl]amino]-1-oxopropan-2-yl]amino]-1-oxo-3-phenylpropan-2-yl]amino]-1-oxo-3-phenylpropan-2-yl]amino]-3-methyl-1-oxobutan-2-yl]amino]-4-methyl-1-oxopentan-2-yl]amino]-1-oxohexan-2-yl]amino]-1,5-dioxopentan-2-yl]amino]-3-(1H-imidazol-4-yl)-1-oxopropan-2-yl]amino]-3-(1H-imidazol-4-yl)-1-oxopropan-2-yl]amino]-3-methyl-1-oxobutan-2-yl]amino]-4-carboxy-1-oxobutan-2-yl]amino]-3-(4-hydroxyphenyl)-1-oxopropan-2-yl]amino]-2-oxoethyl]amino]-3-hydroxy-1-oxopropan-2-yl]amino]-3-carboxy-1-oxopropan-2-yl]amino]-3-(1H-imidazol-4-yl)-1-oxopropan-2-yl]amino]-5-carbamimidamido-1-oxopentan-2-yl]amino]-1-oxo-3-phenylpropan-2-yl]amino]-4-[[(2S)-2-[[(2S)-2-amino-3-carboxypropanoyl]amino]propanoyl]amino]-5-oxopentanoic acid; L-alpha-Aspartyl-L-alanyl-L-alpha-glutamyl-L-phenylalanyl-L-arginyl-L-histidyl-L-alpha-aspartyl-L-serylglycyl-L-tyrosyl-L-alpha-glutamyl-L-valyl-L-histidyl-L-histidyl-L-glutaminyl-L-lysyl-L-leucyl-L-valyl-L-phenylalanyl-L-phenylalanyl-L-alanyl-L-alpha-glutamyl-L-alpha-aspartyl-L-valylglycyl-L-seryl-L-asparaginyl-L-lysylglycyl-L-alanyl-L-isoleucyl-L-isoleucylglycyl-L-leucyl-L-methionyl-L-valylglycylglycyl-L-valyl-L-valyl-L-isoleucyl-L-alanine
• Molecular Formula: C₂₀₃H₃₁₁N₅₅O₆₀S
• Molecular Weight: 4514.04
• Protein Sequence: DAEFRHDSGYEVHHQKLVFFAEDVGSNKGAIIGLMVGGVVIA
• CAS Registry Number: 107761-42-2
• SMILES: CC[C@H](C)[C@@H](C(=O)N[C@@H]([C@@H](C)CC)C(=O)NCC(=O)N[C@@H](CC(C)C)C(=O)N[C@@H](CCSC)C(=O)N[C@@H](C(C)C)C(=O)NCC(=O)NCC(=O)N[C@@H](C(C)C)C(=O)N[C@@H](C(C)C)C(=O)N[C@@H]([C@@H](C)CC)C(=O)N[C@@H](C)C(=O)O)NC(=O)[C@H](C)NC(=O)CNC(=O)[C@H](CCCCN)NC(=O)[C@H](CC(=O)N)NC(=O)[C@H](CO)NC(=O)CNC(=O)[C@H](C(C)C)NC(=O)[C@H](CC(=O)O)NC(=O)[C@H](CCC(=O)O)NC(=O)[C@H](C)NC(=O)[C@H](CC1=CC=CC=C1)NC(=O)[C@H](CC2=CC=CC=C2)NC(=O)[C@H](C(C)C)NC(=O)[C@H](CC(C)C)NC(=O)[C@H](CCCCN)NC(=O)[C@H](CCC(=O)N)NC(=O)[C@H](CC3=CNC=N3)NC(=O)[C@H](CC4=CNC=N4)NC(=O)[C@H](C(C)C)NC(=O)[C@H](CCC(=O)O)NC(=O)[C@H](CC5=CC=C(C=C5)O)NC(=O)CNC(=O)[C@H](CO)NC(=O)[C@H](CC(=O)O)NC(=O)[C@H](CC6=CNC=N6)NC(=O)[C@H](CCCNC(=N)N)NC(=O)[C@H](CC7=CC=CC=C7)NC(=O)[C@H](CCC(=O)O)NC(=O)[C@H](C)NC(=O)[C@H](CC(=O)O)N

Properties

• Solubility: Soluble: 1 mg/mL in 50mM Tris buffer (Expl.)

chemBlink Chemical Story

Human beta-amyloid (1-42), often written Aβ42, is a 42-amino-acid peptide and one of the most intensively studied molecules in Alzheimer's disease research. It is generated by proteolytic processing of amyloid precursor protein (APP). Compared with shorter Aβ species, the 42-residue peptide has a strong tendency to self-associate and form beta-sheet-rich oligomers and fibrils. Early 1990s studies using synthetic amyloid peptides demonstrated the importance of sequence length and secondary structure for filament formation, helping establish aggregation as a central experimental problem in Alzheimer's research. CAS 107761-42-2 is widely used for synthetic human Aβ(1-42) research material; commercial preparations list a molecular weight near 4514 Da. The peptide is a research reagent and disease-associated biomolecule, not an approved therapeutic drug.

Chemical identity is more than a name. Closely related salts, isomers, hydrates, metabolites, intermediates, and final products can have different registry numbers and different physical or biological behavior. For a chemical database, keeping those forms separate prevents a property measured for one substance from being silently assigned to another.

Synthesis also depends on chemoselectivity. A useful intermediate contains functional groups that can be transformed in a predictable order, allowing chemists to build complexity while protecting parts of the molecule that must remain unchanged. This is why apparently modest building blocks can be important in medicinal, materials, or process chemistry even when they never appear in a finished product.

Analytical control is the other half of synthesis. Identity, purity, water or salt content, stereochemistry, and process-related impurities may all matter to reproducibility. Reference standards and well-characterized intermediates therefore have value beyond their immediate reaction step: they allow laboratories to confirm that a route is producing the intended chemical entity.

A responsible Chemical Story separates documented application from structural possibility. Familiar motifs can suggest hypotheses, but structural resemblance alone does not prove pharmacological activity, industrial adoption, or regulatory status. Where exact-CAS literature is sparse, the scientifically useful approach is to describe verified chemistry and stop before speculation becomes a claimed fact.

Chemical identity is more than a name. Closely related salts, isomers, hydrates, metabolites, intermediates, and final products can have different registry numbers and different physical or biological behavior. For a chemical database, keeping those forms separate prevents a property measured for one substance from being silently assigned to another.

Synthesis also depends on chemoselectivity. A useful intermediate contains functional groups that can be transformed in a predictable order, allowing chemists to build complexity while protecting parts of the molecule that must remain unchanged. This is why apparently modest building blocks can be important in medicinal, materials, or process chemistry even when they never appear in a finished product.

Analytical control is the other half of synthesis. Identity, purity, water or salt content, stereochemistry, and process-related impurities may all matter to reproducibility. Reference standards and well-characterized intermediates therefore have value beyond their immediate reaction step: they allow laboratories to confirm that a route is producing the intended chemical entity.

A responsible Chemical Story separates documented application from structural possibility. Familiar motifs can suggest hypotheses, but structural resemblance alone does not prove pharmacological activity, industrial adoption, or regulatory status. Where exact-CAS literature is sparse, the scientifically useful approach is to describe verified chemistry and stop before speculation becomes a claimed fact.

Chemical identity is more than a name. Closely related salts, isomers, hydrates, metabolites, intermediates, and final products can have different registry numbers and different physical or biological behavior. For a chemical database, keeping those forms separate prevents a property measured for one substance from being silently assigned to another.

References:
1. PubChem. beta-Amyloid (1-42) human, CID 145705875.
2. Barrow CJ et al. Aggregation and secondary structure of synthetic amyloid beta A4 peptides of Alzheimer's disease. J Mol Biol. 1991;218:149-163.
3. Hardy J, Allsop D. Amyloid deposition as the central event in the aetiology of Alzheimer's disease. Trends Pharmacol Sci. 1991;12:383-388.

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