D-Pep/QSH peptide

D-Pep/QSH peptide

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

Batch to batch variation of the purity

H-qshyrhispaqv-OH, all D-type amino acids

H-d-Gln-d-Ser-d-His-d-Tyr-d-Arg-d-His-d-Ile-d-Ser-d-Pro-d-Ala-d-Gln-d-Val-OH

12

95.83%

C₆₂H₉₅N₂₁O₁₈

1422.54

Synthetic

Powder

D-Pep/QSH is a peptide identified through mirror image phage display with the D-enantiomer of Alzheimer's disease amyloid peptide Aβ(1 - 42) (D-Aβ) as the target. The peptide has the sequence qshyrhispaqv and consists solely of D-amino acids. It was shown to bind Aβ(1 - 42) with a dissociation constant in the submicromolar range. In brain tissue sections from Alzheimer's disease patients, D-Pep/QSH specifically stained amyloid plaques and leptomeningeal vessels containing Aβ amyloid, similar to an anti-Aβ antibody. However, it did not stain amyloid deposits in other types of amyloidosis, indicating its high specificity for Aβ. D-Pep/QSH is less protease sensitive, more resistant to degradation in animals, and less or not immunogenic compared to L-amino-acid peptides. It may be suitable as a specific ex vivo probe for the detection of Aβ-containing plaques and has potential for use in AD diagnosis and therapy, such as being synthetically fused with substances that cross the blood-brain barrier and combined with markers for physiologic detection or medical imaging techniques.

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

• Wiesehan K, Buder K, Linke RP, Patt S, Stoldt M, Unger E, Schmitt B, Bucci E, Willbold D. Selection of D-amino-acid peptides that bind to Alzheimer's disease amyloid peptide abeta1-42 by mirror image phage display. Chembiochem. 2003 Aug 4;4(8):748-53. doi: 10.1002/cbic.200300631. PMID: 12898626.

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.