Septide peptide

Septide peptide

• Handling and Storage of Synthetic Peptides
• Material Safety Data Sheets (MSDS)

Batch to batch variation of the purity

Pyr-FFPLM-NH2

Pyr-Phe-Phe-Pro-Leu-Met-NH2

5

95.82%

C₃₉H₅₃N₇O₇S

763.94

79775-19-2

119137

Synthetic

Powder

Septide is a synthetic peptide with the amino acid sequence [pGlu⁶, Pro⁹]Substance P^9-11. It is known to have tachykinin-like actions despite its apparent lack of binding to any known tachykinin receptor initially. However, later studies have shown that Septide binds to the NK-1 receptor with high affinity.
Binding Affinity to NK-1 Receptor: In homologous binding assays, Septide has a Kd value of 0.55 ± 0.03 nM, indicating high-affinity binding to the NK-1 receptor. In competition against radiolabeled NKA, Septide also appears as a high-affinity ligand on the NK-1 receptor, with a Ki value of 1.90 ± 0.35 nM. Similarly, NKA can compete with high affinity for Septide binding on the NK-1 receptor, with a Ki value of 0.21 ± 0.01 nM.
Role in Tachykinin Receptor Actions: The finding that Septide binds with high affinity to the NK-1 receptor suggests that the NK-1 receptor may function as a general tachykinin receptor, binding subnanomolar concentrations of not only the naturally occurring neuropeptides substance P (SP) and neurokinin A (NKA), but also the synthetic peptide Septide. This observation challenges the previous notion that a special "septide receptor" or an extra NKA binding receptor might exist.
Overall, Septide is an important peptide in the study of tachykinin receptors and their functions, providing insights into the complex interactions between peptides and receptors in the nervous system.

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

• Hastrup H, Schwartz TW. Septide and neurokinin A are high-affinity ligands on the NK-1 receptor: evidence from homologous versus heterologous binding analysis. FEBS Lett. 1996 Dec 16;399(3):264-6. doi: 10.1016/s0014-5793(96)01337-3. PMID: 8985159.

Trifluoroacetic acid (TFA) has a significant impact on peptides due to its role in the peptide synthesis process.

TFA is essential for the protonation of peptides that lack basic amino acids such as Arginine (Arg), Histidine (His), and Lysine (Lys), or ones that have blocked N-termini. As a result, peptides often contain TFA salts in the final product.

TFA residues, when present in custom peptides, can cause unpredictable fluctuations in experimental data. At a nanomolar (nM) level, TFA can influence cell experiments, hindering cell growth at low concentrations (as low as 10 nM) and promoting it at higher doses (0.5–7.0 mM). It can also serve as an allosteric regulator on the GlyR of glycine receptors, thereby increasing receptor activity at lower glycine concentrations.

In an in vivo setting, TFA can trifluoroacetylate amino groups in proteins and phospholipids, inducing potentially unwanted antibody responses. Moreover, TFA can impact structure studies as it affects spectrum absorption.