ClearPoint™ BSA (347-359), Isotopic labeled, Mass Spec Standard

Product Name: ClearPoint™ BSA (347-359), Isotopic labeled, Mass Spec Standard

Sequence One Letter Code: DAF-L*-GSF-L*-YEYSR [L* = L(U13C6, 15N)]

Sequence Three Letter Code: H-Asp-Ala-Phe-Leu*-Gly-Ser-Phe-Leu*-Tyr-Glu-Tyr-Ser-Arg-OH [Leu* = Leu(U13C6, 15N)]

Molecular Weight: 1581.8

Purity: 95%

Form: Lyophilized

Storage Conditions: - 20 °C

Research Area: Stable Isotope-labeled Compounds

Source / Species: Bovine

Conjugation: Unconjugated

Code Nacres: NA.26

Application: ClearPoint™ BSA (347–359), Isotopic Labeled, is a synthetic bovine serum albumin–derived peptide engineered as a quantitative internal standard for mass spectrometry workflows. The sequence incorporates a heavy isotope–labeled leucine residue containing ^13C₆ and ^15N₁, generating a defined mass shift without altering chemical properties or chromatographic behavior. This isotopic design enables accurate isotope dilution mass spectrometry–based quantification of corresponding native peptides with high precision and reproducibility. The peptide serves as a reliable calibration and normalization standard in LC–MS/MS analyses. ClearPoint™ BSA (347–359) is widely used for method development, assay validation, and quality control in quantitative proteomics. Its structural equivalence to the native sequence ensures consistent ionization efficiency and fragmentation patterns, supporting robust measurement of protein abundance in complex biological samples across research and bioanalytical applications.

Current Research: ClearPoint™ BSA (347–359), Isotopic Labeled, is a synthetic peptide derived from bovine serum albumin (BSA) and specifically engineered as a quantitative internal standard for mass spectrometry–based proteomic workflows. The peptide corresponds to residues 347–359 of BSA and incorporates a heavy isotope–labeled leucine residue containing ^13C₆ and ^15N₁. This isotopic substitution introduces a defined mass shift while preserving the peptide’s chemical structure, chromatographic properties, and ionization behavior. The incorporation of stable isotopes enables application in isotope dilution mass spectrometry (IDMS), a gold-standard approach for accurate and reproducible quantification. Because the labeled peptide is chemically identical to the native sequence except for its mass difference, it co-elutes with the endogenous counterpart during liquid chromatography and exhibits comparable ionization efficiency. This ensures that both species experience identical matrix effects and instrument conditions, minimizing analytical variability. In LC–MS/MS workflows, ClearPoint™ BSA (347–359) functions as a calibration and normalization reference. By spiking a known quantity of the isotopically labeled peptide into samples, researchers can quantify the corresponding native peptide based on signal intensity ratios. The defined mass shift allows unambiguous distinction between labeled and endogenous species during multiple reaction monitoring (MRM) or parallel reaction monitoring (PRM) analysis. This strategy supports precise determination of peptide abundance across a wide dynamic range. The peptide is particularly valuable in quantitative proteomics method development and assay validation. During optimization of chromatographic separation, mass spectrometric parameters, and fragmentation transitions, the isotopically labeled standard provides a consistent benchmark for evaluating sensitivity, linearity, and reproducibility. It also facilitates assessment of sample preparation efficiency, digestion consistency, and instrument performance. ClearPoint™ BSA (347–359) is widely applied in quality control workflows to monitor analytical stability across batches and over extended analytical runs. Because it mirrors the physicochemical behavior of the native peptide, it serves as an internal control for retention time stability, peak shape consistency, and fragmentation pattern reproducibility. This is especially important in regulated bioanalytical environments and large-scale proteomic studies where inter-run comparability is critical. The structural equivalence of the isotopically labeled peptide ensures consistent fragmentation spectra in tandem mass spectrometry. Product ion transitions can be selected to match those of the native peptide, differing only in precursor mass. This simplifies assay design and enhances quantification accuracy by reducing variability associated with differential fragmentation. In complex biological matrices such as plasma, serum, or cell lysates, matrix effects can influence ion suppression or enhancement. The co-eluting heavy-labeled standard compensates for these effects by providing a direct internal reference, improving quantitation robustness in heterogeneous samples. Overall, ClearPoint™ BSA (347–359), Isotopic Labeled, provides a reliable and precise internal standard for LC–MS/MS–based quantitative proteomics. Its defined isotopic mass shift, chromatographic equivalence to the native sequence, and compatibility with isotope dilution strategies make it an essential tool for method validation, assay normalization, and high-confidence measurement of protein abundance in research and bioanalytical applications.