What is thymosin alpha 1?
Thymosin alpha 1 is a 28-amino-acid peptide with an acetylated N-terminus, matching the start of a larger protein, prothymosin alpha. It was first sequenced in 1977 from calf thymus and is made synthetically as the drug thymalfasin, approved in a number of countries outside the United States. Here is its structure, origin, research and status, and how it differs from thymosin beta 4.
Thymosin alpha 1 in one table.
| Sequence | Ac-SDAAVDTSSEITTKDLKEKKEVVEEAEN |
|---|---|
| Length | 28 amino acids, N-terminally acetylated |
| Formula | C129H215N33O55 |
| Molecular weight | 3108.3 g/mol (monoisotopic 3106.504) |
| PubChem CID | 16130571 (thymalfasin) |
| Source protein | Prothymosin alpha (PTMA gene), residues 2 to 29 |
| Drug name | Thymalfasin |
| Status | Approved in a number of countries outside the US; not FDA approved |
Formula and masses from Helion's peptide molecular weight calculator with the acetyl cap, matching PubChem.
From thymosin fraction 5.
In the 1960s and 1970s, Allan Goldstein's group extracted a mixture of peptides from calf thymus, called thymosin fraction 5, and in 1977 isolated and sequenced one of them: thymosin alpha 1. Later work identified prothymosin alpha, a larger protein found in many tissues, as its source; thymosin alpha 1 matches that protein's N-terminal residues after the first methionine, with the serine acetylated.
Immune signaling in cells and mice.
Much of the research on thymosin alpha 1 concerns immune cells. A 2004 study found that it activates dendritic cells through Toll-like receptor signaling in cell and mouse models of fungal infection, and a 1999 study reported that it stimulated maturation of CD34+ stem cells toward T cells in an in vitro thymic co-culture model.
Approved abroad, not in the US.
As the drug thymalfasin, it was described in 2009 as approved in over 35 countries for hepatitis B and C and as an immune stimulant and adjuvant. It has no FDA approval. Thymosin alpha 1 was nominated for pharmacy compounding and placed in Category 2, the FDA's group of bulk substances that may present significant safety risks; the nomination was later withdrawn, and the FDA list now shows it among withdrawn nominations, saying the safety-related information is inadequate to understand the extent of any safety issues. Helion supplies compounds for laboratory research use only.
Same name, unrelated peptides.
Thymosin alpha 1 and thymosin beta 4 share a name because both were first found in thymosin fraction 5, not because they are related. They come from different genes on different chromosomes, PTMA and TMSB4X, and belong to different protein families. Thymosin beta 4 is a 43-amino-acid peptide that binds actin monomers and keeps them from polymerizing; thymosin alpha 1 is 28 amino acids and is studied for immune signaling.
Not supplied.
Helion does not supply thymosin alpha 1. It supplies TB-500, the acetylated 17-23 fragment of thymosin beta 4, in the Wolverine blend with BPC-157, for laboratory research use only.
Specs and storage by compound.
Questions (7)
What is thymosin alpha 1?
A 28-amino-acid peptide with an acetylated N-terminus, matching residues 2 to 29 of prothymosin alpha. It was first sequenced in 1977 from calf thymus.
What is thymalfasin?
The drug name for synthetic thymosin alpha 1, approved in a number of countries outside the United States.
What is the thymosin alpha 1 sequence?
Ac-SDAAVDTSSEITTKDLKEKKEVVEEAEN, 28 residues with an acetylated serine at the N-terminus.
What is the molecular weight of thymosin alpha 1?
3108.3 g/mol (C129H215N33O55).
Is thymosin alpha 1 the same as thymosin beta 4?
No. They share a name and a source extract but come from different genes and families. Thymosin beta 4 is a 43-residue actin-binding peptide.
Is thymosin alpha 1 approved?
As thymalfasin it is approved in a number of countries outside the US. It is not approved by the FDA.
Does Helion sell thymosin alpha 1?
No. Helion supplies TB-500, a thymosin beta 4 fragment, in the Wolverine blend, for laboratory research use only.
Published studies (7)
- Thymosin alpha1: isolation and sequence analysis of an immunologically active thymic polypeptide
- Prothymosin alpha: isolation and properties of the major immunoreactive form of thymosin alpha 1 in rat thymus
- From lab to bedside: emerging clinical applications of thymosin alpha 1
- Thymosin alpha 1 activates dendritic cells for antifungal Th1 resistance through toll-like receptor signaling
- Thymosin-alpha1 stimulates maturation of CD34+ stem cells into CD3+4+ cells in an in vitro thymic epithelia organ coculture model
- The thymosins. Prothymosin alpha, parathymosin, and beta-thymosins: structure and function
- Thymosin beta 4 and Fx, an actin-sequestering peptide, are indistinguishable
Citations from PubMed for reference. They describe the compound in the literature, not any Helion lot, and nothing here is guidance on use.