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Molecular Weight
Purity
Storage
Appearance
Solubility
01
P21, also written P021, is a small synthetic peptide derived from ciliary neurotrophic factor (CNTF). Its sequence, Ac-Asp-Gly-Gly-Leu, comes from an active region of CNTF identified by epitope mapping, and it carries an adamantane-based carboxamide group at the C-terminus.
The adamantane unit was added to increase lipophilicity and resistance to enzymatic breakdown. P21 has been studied mainly by one research group in rodent models of neurodegeneration, where it has been examined for effects on neurogenesis, neurotrophic factor expression and tau-related pathology. It is supplied as a lyophilized reference material for in vitro research only.
02
P21 combines a short CNTF-derived sequence with a synthetic C-terminal group.
CNTF-derived core
Asp-Gly-Gly-Leu corresponds to residues 148–151 of human CNTF, within a longer peptide fragment found to be active in earlier epitope-mapping work.
N-terminal acetyl group
Blocks aminopeptidases and removes the N-terminal positive charge.
Adamantane group
Adamantane is a rigid, cage-shaped hydrocarbon (C₁₀). Here it is incorporated as a 3-aminoadamantane-1-carboxamide unit at the C-terminus. It is very hydrophobic and bulky, which increases lipophilicity and sterically hinders C-terminal enzymatic cleavage.
Naming
The C-terminal unit is sometimes written as “adamantylglycine” (AG), giving the shorthand Ac-DGGL(AG)-NH₂. Registry entries describe it as a 3-aminoadamantane-1-carboxamide attached to Leu.
03
Published research on P21 comes mainly from rodent and cell studies.
Neurogenesis and neurotrophic factors
Studies have reported increased BDNF expression and enhanced hippocampal neurogenesis in mice, with downstream TrkB/PI3K/Akt signalling and reduced GSK-3β activity proposed as mechanisms.
LIF/CNTF signalling
P21 has been described as modulating leukemia inhibitory factor (LIF) signalling, which is related to the CNTF pathway.
Neurodegeneration models
Work in transgenic Alzheimer’s disease mouse models examined effects on tau pathology, synaptic markers and cognitive tests.
Replication
Independent replication of some findings has been limited, which is important context when interpreting the literature.
These findings are cited as research context only; no effects are claimed for this material.
04
Neural progenitor assays
Used in cell-culture studies of neural progenitor proliferation and differentiation.
Neurotrophic signalling
A tool compound in experiments measuring BDNF expression and TrkB/Akt/GSK-3β signalling.
Adamantane-peptide analytics
A model for methods analysing short peptides with bulky hydrophobic terminal groups, alongside Adamax.
05
Storage
Store the lyophilized powder at −20 °C, sealed, desiccated and protected from light.
Reconstitution
The adamantane group reduces water solubility. Water or dilute acetic acid usually works at moderate concentrations; a small amount of DMSO can help for concentrated stocks.
Chemical stability
There is no methionine, cysteine or tryptophan. Asp1 is the main chemical weak point and can slowly form an aspartimide, fastest in the mildly acidic range (around pH 4–6).
Solutions
Prepare fresh or freeze single-use aliquots, and use low-binding polypropylene tubes.
06
Analysis must confirm the short peptide core and both terminal groups.
HPLC
Reversed-phase C18 with a TFA gradient. The adamantane group gives much stronger retention than the short sequence alone would suggest. Detect at about 214 nm; there are no aromatic residues.
Mass spectrometry
Positive-mode ESI shows [M+H]⁺ at m/z 579.3 (monoisotopic). MS/MS confirms the acetyl group and the adamantane-containing C-terminal fragment.
Impurity profile
Typical checks include the non-acetylated form, deletion sequences, isoAsp variants and counter-ion content.
07
From ciliary neurotrophic factor (CNTF). Its Asp-Gly-Gly-Leu sequence corresponds to residues 148–151 of human CNTF, with an N-terminal acetyl group and a C-terminal adamantane carboxamide.
Yes. P021 is the name used in the original research literature; P21 is a common shorthand for the same peptide.
The adamantane group increases lipophilicity and resistance to enzymatic breakdown. The same terminal unit is used in Adamax.
C₂₇H₄₂N₆O₈, about 578.7 g/mol, with [M+H]⁺ at m/z 579.3 in ESI-MS.
Most studies come from a single research group, mainly in rodent models, and independent replication has been limited. Results should be interpreted with that in mind.
No. It is supplied strictly as a reference compound for laboratory and analytical research and is not for human or animal use.
P21 (P021) Research Reference. (2026). Pure Peptides Labs Research Catalogue. Retrieved from https://purepeptideslabs.net/research-catalogue/neurochemical-research-peptides/p21/
Materials listed on this platform are supported by independent testing and published documentation for laboratory research contexts.
