Compound monograph
Ac-SDKP (Goralatide)
Ac-SDKP is the acetylated N-terminal tetrapeptide of thymosin beta-4, generated from the parent by sequential enzymatic processing.
01
Identity & nomenclature
Ac-SDKP is the acetylated N-terminal tetrapeptide of thymosin beta-4, generated from the parent by sequential enzymatic processing.
Ac-SDKP is not thymosin beta-4 and not a generic TB-500 fragment. It is one specifically processed N-terminal tetrapeptide and is not a stand-in for the parent's other sequence regions. Release and degradation are also different processes: meprin-alpha and prolyl oligopeptidase participate in generating it, while angiotensin-converting enzyme hydrolyses it. ACE must not be recorded as the releasing mechanism.
Declared aliases and development codes: Ac-SDKP, Seraspenide, N-acetyl-seryl-aspartyl-lysyl-proline.
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Molecular properties
| Molecular formula | C20H33N5O9 |
|---|---|
| Molecular mass | 487.51 Da |
| CAS Registry Number | 120081-14-3 |
| PubChem CID | 65938 |
| UNII | H041538E9P |
| One-letter sequence | SDKP |
| Three-letter sequence | Ac–Ser–Asp–Lys–Pro–OH |
Four residues, all L, N-terminally acetylated with a free C-terminal carboxyl. The acetyl sits on the serine alpha-amino group. An acetyl on the lysine side chain instead would preserve the elemental composition while describing a different molecule.
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Structural characteristics
The release pathway is the best-characterised thing about this compound, and it is sequential rather than direct. In a purified system neither meprin-alpha nor prolyl oligopeptidase alone released Ac-SDKP from intact thymosin beta-4; only both together did, supported by inhibitor experiments and by kidneys from meprin-alpha knockout animals failing to release it. Earlier work had identified prolyl oligopeptidase as responsible, and the later finding refines that rather than overturning it. Separate work comparing parent, fragment, and cleavage inhibition supports a conditional statement — that some thymosin beta-4-associated effects depend on Ac-SDKP being generated — and does not support the converse, that activity measured with isolated Ac-SDKP can be attributed to the intact parent. No direct cognate receptor is established.
Terminal features: N-terminal acetylation, Free C-terminal carboxyl.
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Molecular targets & mechanisms
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Analytical considerations
Confirmation needs N-terminal rather than lysine-side-chain acetylation established by an orthogonal method, since the two are identical by mass. Ordinary aspartate versus isoaspartate connectivity also survives an intact-mass match. A terminal acid and an amide differ in exact mass and should be distinguished explicitly. When studying formation from the parent, measure both the intact parent and the released tetrapeptide; a downstream cellular response is not evidence that cleavage occurred.
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Verified bibliography
- The anti-inflammatory peptide Ac-SDKP is released from thymosin-β4 by renal meprin-α and prolyl oligopeptidase.current
Kumar N, Nakagawa P, Janic B, Romero CA, Worou ME, Monu SR, Peterson EL, Shaw J, Valeriote F, Ongeri EM, Niyitegeka JM, Rhaleb NE, Carretero OA
American journal of physiology. Renal physiology · 2016-03-09 · Journal Article
- Prolyl oligopeptidase is involved in release of the antifibrotic peptide Ac-SDKP.current
Cavasin MA, Rhaleb NE, Yang XP, Carretero OA
Hypertension (Dallas, Tex. : 1979) · 2004-03-22 · Journal Article
- Thymosin β4 and its degradation product, Ac-SDKP, are novel reparative factors in renal fibrosis.current
Zuo Y, Chun B, Potthoff SA, Kazi N, Brolin TJ, Orhan D, Yang HC, Ma LJ, Kon V, Myöhänen T, Rhaleb NE, Carretero OA, Fogo AB
Kidney international · 2013-06-05 · Journal Article
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Methodology & citation verification
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