What is P-21?
P-21, carried in our catalog under the synonym P021, is described in the literature as a peptidomimetic developed from an active fragment of ciliary neurotrophic factor. Our molecular dataset holds no CAS number, formula, molecular weight or sequence for this entry, so none of those values are quoted here; a batch's figures are stated on its certificate of analysis.
What can be said without those records is that the compound belongs to the peptidomimetic class rather than the straightforward peptide class. Molecules of that kind take a short active stretch of a parent protein and cap or replace parts of it with non-peptide chemistry, for resistance to peptidase cleavage and better membrane behaviour.
Research interest centres on neurotrophic signalling. Rodent work has used the compound to model adult hippocampal neurogenesis and to probe brain-derived neurotrophic factor expression, with reported inhibition of leukaemia inhibitory factor signalling proposed as one way a fragment can act in the opposite direction to the full-length cytokine. The literature base is small, the mechanism is not independently settled, and comparative work against other neurotrophic tool compounds is sparse.
Reconstitution & handling
Sterile or bacteriostatic water is the usual starting diluent. Because our records carry no solubility data for this entry, add a small volume first and check that the solution runs clear, with no haze or particulate, before adding the rest. Swirl, do not shake. Concentration is the labelled mass divided by the total diluent volume.
Storage & stability
The sealed lyophilized vial belongs at -20 °C, desiccated and shielded from light, the condition the dry cake is packaged for. Once in solution, hold at 2 to 8 °C and divide into single-use aliquots rather than returning a working stock to the freezer. Where a degradation profile is not well described, as here, short solution hold times and fresh preparation are the conservative choices.
How it's tested
Release testing runs reversed-phase HPLC at 214 and 220 nm against a main-peak purity threshold of 99 percent or better. Identity is confirmed by mass spectrometry, the observed mass compared against the theoretical mass calculated for the batch structure rather than any value quoted here. Net peptide content and water are reported separately, and the lot-matched certificate of analysis is available on request.