Other · Endogenous N-acetylated regulatory tetrapeptide
N-acetyl-seryl-aspartyl-lysyl-proline (Ac-SDKP)
Also known as Ac-SDKP; N-acetyl-Ser-Asp-Lys-Pro
An endogenous acetylated tetrapeptide studied in progenitor-cell cycling, extracellular matrix signalling and ACE-dependent metabolism.
- Length
- 4 amino acids
- Half-life
- Not well characterised
- Mechanism
- Ac-SDKP influences haematopoietic progenitor cycling and fibroblast-associated signalling in experimental models, with modulation of TGF-β/Smad responses reported. No definitive cognate receptor has been established; angiotensin-converting enzyme is a major degradation enzyme rather than an established signalling receptor for the peptide.
- Studied in
- Haematopoietic progenitor cultures, fibroblast assays and rodent tissue-remodelling models investigate cell-cycle regulation, extracellular matrix production and peptide metabolism.
About N-acetyl-seryl-aspartyl-lysyl-proline (Ac-SDKP)
Ac-SDKP is an endogenous tetrapeptide consisting of N-acetylated serine followed by aspartate, lysine and proline. It was originally isolated from bone marrow extracts during investigations of factors regulating haematopoietic progenitor proliferation. Its sequence corresponds to the acetylated N-terminus of thymosin β4. Generation from this larger precursor involves sequential proteolytic processing, with meprin α and prolyl oligopeptidase implicated in the pathway. The N-terminal acetyl group is an integral structural feature, not an interchangeable formulation detail.
A major determinant of Ac-SDKP persistence is cleavage by angiotensin-converting enzyme, particularly its N-terminal catalytic domain. Consequently, stability depends strongly on enzyme activity and sample handling, and one half-life value cannot describe every experimental matrix. Fibroblast and tissue-remodelling studies examine collagen production, TGF-β-associated signalling and inflammatory-cell interactions, while progenitor-cell assays address cell-cycle entry. These experimental effects have not established a definitive cognate receptor, and the enzymes responsible for turnover should be distinguished from signalling targets.
Laboratory notes
- Confirm N-terminal acetylation and distinguish Ac-SDKP from the unacetylated SDKP sequence by an appropriate analytical method.
- For biological samples, validate rapid processing and a peptide-preservation strategy because ACE-dependent degradation can alter measured abundance.
- In quantitative assays, assess matrix effects and recovery; a stable-isotope-labelled internal standard is useful for mass-spectrometric analysis.
Storage and reconstitution basics: storage guide.
Questions about N-acetyl-seryl-aspartyl-lysyl-proline (Ac-SDKP)
What is the relationship between Ac-SDKP and thymosin β4?
Ac-SDKP corresponds to the N-terminal four residues of acetylated thymosin β4 and can be generated through sequential proteolytic processing of that precursor.
Is ACE the receptor for Ac-SDKP?
No. ACE is a major enzyme responsible for Ac-SDKP degradation, with its N-terminal catalytic domain particularly important. This metabolic role does not establish receptor signalling.
Why must sample processing be standardised?
Continued peptide degradation after collection can change the measured concentration. Collection conditions, processing time, temperature and analytical recovery should therefore be validated together.
Is N-acetyl-seryl-aspartyl-lysyl-proline (Ac-SDKP) for human use?
No. It is supplied strictly for in-vitro laboratory research and is not for human or animal consumption.
Related research peptides
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