β-CGRP, human peptide

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

Batch to batch variation of the purity

Calcitonin gene-related peptide (CGRP) is a 37-amino acid neuropeptide derived from alternative RNA processing of the calcitonin gene. It exists in two major isoforms, α- and β-CGRP, which share high homology and similar biological activities. CGRP belongs to a peptide family that acts on a unique receptor family composed of the calcitonin receptor-like receptor (CLR) and receptor activity-modifying protein 1 (RAMP1), essential for its functionality. CGRP is a potent vasodilator, primarily released from sensory nerves, and is implicated in cardiovascular regulation and pain pathways. The peptide is localized extensively in perivascular sensory fibers and plays a role in neurogenic inflammation and vascular protection.

CGRP is synthesized in sensory neurons and stored in dense-core vesicles, with release mediated by calcium-dependent exocytosis. Its vasodilatory effects are mediated through cAMP-dependent pathways, involving both endothelium-dependent and -independent mechanisms. CGRP also modulates immune responses and has been implicated in conditions such as migraine, where its release contributes to vasodilation and nociceptive signaling. The peptide's structure includes a disulfide-bonded N-terminal ring, an α-helical domain, and a C-terminal region critical for receptor binding. CGRP metabolism involves enzymes such as neutral endopeptidase and endothelin-converting enzyme-1, which regulate its bioavailability.

• Russell FA, King R, Smillie SJ, Kodji X, Brain SD. Calcitonin gene-related peptide: physiology and pathophysiology. Physiol Rev. 2014 Oct;94(4):1099-142. doi: 10.1152/physrev.00034.2013. PMID: 25287861; PMCID: PMC4187032.

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.