In the realm of biochemical researc 24 Sept 2020—Molecular Weight.4514.08; Formula. C203H311N55O60S ; Storage. Store at -20°C ; Purity. ≥95% (HPLC) ; CAS Number. 107761-42-2 Read more h and synthetic peptide analysis, few sequences are as frequently discussed as the 42-amino acid isoform of the amyloid β peptide. Whether you are setting up assays or calibrating your analytical equipment, understanding the precise molecular weight and structural characteristics of this peptide is foundational. My experience with these reagents has shown that consistency is key, particularly when dealing with the amyloid-β peptide 1-42 molecular weight.
Technical Specifications and Data
When sourcing this material, the molecular weight is often cited as 4514 Da (or 4514.1 g/mol). From my observations, it is vital to distinguish between the human and rat isoforms. While the human amyloid variant typically presents at 4514.08 to 4514.14, the rat/mouse version is slightly lighter, with a molecular weight: 4417.95 or 4417.99 (often rounded to 4418 Da).
Below is a breakdown of the typical data points I look for in a Certificate of Analysis:
* Molecular Formula: C203H311N55O60S (for the standard human sequence).
* Structure: The peptide transitions from helical to β-sheet, which significantly impacts how it behaves in solution.
* Variations: Beta Amyloid (1-42), human I have worked with modified versions, such as 5-FAM-labeled variants, which push the formula weight to 4872.36.
Practical Considerations for Handling
Working with these peptides requires strict adherence to storage and handling protocols. Most high-purity samples arrive as a lyophilized powder. When reconstituting, I have found that the solubility is highly batch-dependent. Some researchers prefer using 1% NH4OH or HFIP (hexafluoroisopropanol) to ensure the amyloid β monomerizes effectively before use.
Why Precision Matters
The molecular mass of the Amyloid precursor protein (APP) is approximately ~100 kD, but the specific 1-42 fragment is a small, 42-residue peptide. If you are using a peptide calculator, you will see the 4514.1 value used as a standard for the 1-42 sequence. When I receive a new batch, I always verify the molecular weight: 4513.05 or simi Amyloid β-peptide (42-1) (human) lar values against the provided datasheet to ensure the salt form (often TFA) is accounted for in the calculations.
Insights on Research Consistency
In my personal workflow, I emphasize the following:
1. Storage: Always keep these vials at -20°C or -70°C. Degradation can shift the observed purity, which should be >95% via HPLC.
2. Terminology: Whether you refer to it as amyloid β, Aβ42, or the beta-amyloid peptide, the analytical standard remains the same.
3. Expectations: The 4514.04 or 4514.08 figures are theoretical. Always check your specific lot, as small variations in purity can affect the perceived molecular weight.
By focusing on the verified molecular 24 Sept 2020—Molecular Weight.4514.08; Formula. C203H311N55O60S ; Storage. Store at -20°C ; Purity. ≥95% (HPLC) ; CAS Number. 107761-42-2 Read more weight and chemical CalculatedMolecular Weight, 4514.1.Molecular Formula, C203H311N55O60S. Form, Lyophilized powder. Purity, > 95%. Storage, -20℃. Shipping, ice bag. Note, For Read more formula, one can maintain higher standards in experimental setups. The structure and purity of the amyloid β peptide 1-42 are critical, and I have found that paying attention to these minor details—such as the difference between the 4418.02 rat sequence and the 4514.10 human sequence—prevents significant errors in data interpretation. Always prioritize materials fro Molecular weight: 874 g/mol Overview: High fluorescence intensity; High photostability; Less pH-sensitive; Excellent batch-to-batch reproducibility Read more m reputable sources that provide clear documentation on their molecular weight and synthetic purity.