SS-18 peptide

SS-18 peptide

• COA/MS/HPLC Report
• Handling and Storage of Synthetic Peptides
• Material Safety Data Sheets (MSDS)

Batch to batch variation of the purity

SGELEQEEERLSKEWEDS

H-Ser-Gly-Glu-Leu-Glu-Gln-Glu-Glu-Glu-Arg-Leu-Ser-Lys-Glu-Trp-Glu-Asp-Ser-OH

18

95.34%

C₉₀H₁₃₈N₂₄O₃₉

2180.19

Synthetic

Powder

SS-18 is a peptide derived from human chromogranin A (CgA). It consists of amino acid residues 304 - 321 of CgA. The detected mass (M + H)+ of SS-18 is 2180.85 Da, with a calculated mass of 2180.22 Da. The processing sites involved in its generation are between K at position 304 and KR at position 321, and putative enzymes responsible for its formation include prohormone convertase 1/3, prohormone convertase 2, and carboxypeptidase H.
SS-18 was identified through a series of chromatographic fractionation and mass spectrometric analysis. The extract of human insulinoma was first subjected to gel permeation chromatography and then RP-HPLC. In the RP-HPLC analysis of pool 3, SS-18 was detected by MALDI-TOF mass spectrometry. It was found that SS-18 is difficult to resolve from peptide WE-14 by RP-HPLC and is consistently present in preparations of the latter peptide.
This peptide is not only identified in human insulinoma but also in the extract of a mid-gut carcinoid tumour, indicating its presence in multiple neuroendocrine tumour types. The identification of SS-18 provides valuable information for understanding the endogenous processing of CgA and may have implications for further studies on the biological functions of CgA-derived peptides.

Normally, this peptide will be delivered in lyophilized form and should be stored in a freezer at or below -20 °C. For more details, please refer to the manual: Handling and Storage of Synthetic Peptides

Trifluoroacetic acid (TFA) is a common counterion from the purification process using High-Performance Liquid Chromatography (HPLC). The presence of TFA can affect the peptide's net weight, appearance, and solubility.

Impact on Net Weight: The TFA salt contributes to the total mass of the product. In most cases, the peptide content constitutes >80% of the total weight, with TFA accounting for the remainder.

Solubility: TFA salts generally enhance the solubility of peptides in aqueous solutions.

In Biological Assays: For most standard in vitro assays, the residual TFA levels do not cause interference. However, for highly sensitive cellular or biochemical studies, please be aware of its presence.