What is PE 22-28?
PE 22-28 is listed in our records under the synonym spadin analogue, a TREK-1 modulator. The dataset carries no CAS number, formula, molecular weight, sequence or residue count for this handle, so no such values appear here. The numeric part of the name refers to a span of the parent spadin sequence, not to any measured property.
Spadin itself is a fragment released during maturation of sortilin, a sorting receptor of the vacuolar protein sorting 10 family. The shortened analogues in this series keep the channel-blocking element of the parent while reducing the length exposed to peptidase attack, the usual motivation for trimming a propeptide fragment to its minimum active span.
The published work centres on TREK-1, a two-pore-domain potassium channel. Electrophysiology in transfected cells reports blockade of TREK-1 current, and rodent behavioural studies have used spadin and its shortened analogues to model depressive-like behaviour and to examine hippocampal neurogenesis and synaptogenesis markers. Selectivity against other two-pore-domain channels, the plasma stability of the shortened forms, and whether the behavioural readouts depend solely on TREK-1 all remain open.
Reconstitution & handling
Sterile or bacteriostatic water is the usual diluent for short hydrophilic peptides of this kind. With no solubility record on file, add a small aliquot first and confirm the cake clears before adding the rest. Direct the stream at the vial wall and swirl gently. Concentration is the labelled mass divided by the total diluent volume.
Storage & stability
Hold the sealed dry vial at -20 °C, desiccated and out of the light. Short peptides in dilute aqueous solution lose material to adsorption on glass and plastic as well as to hydrolysis, so reconstituted stock should be aliquoted at a workable concentration, held at 2 to 8 °C and used without repeated freeze-thaw.
How it's tested
Lots are assessed by reversed-phase HPLC at 214 and 220 nm and released against a 99 percent or better main-peak purity specification. Mass spectrometric identity is checked against the theoretical mass for the batch structure. Because short peptides are supplied as salts, net peptide content is reported separately from purity, along with water and residual counterion. A lot-matched certificate of analysis is available on request.