Thymosin Alpha-1 vs Thymosin Beta-4: Same Name, Different Molecules
The "thymosins" were named for where they were found, not for what they do. Thymosin Alpha-1 and Thymosin Beta-4 are unrelated in sequence and are studied for different reasons.
Research blog: general laboratory-science and literature context. Not medical advice. Sealed Peptides materials are for laboratory research use only, and are not for human or veterinary use.
A name from an extract
In the 1960s and 1970s, researchers separated a calf thymus extract called thymosin fraction 5 into many peptides and named them by their position on an electrophoresis gel: alpha, beta and gamma. The name says where a peptide was isolated, not that the peptides are related.
Thymosin Alpha-1
Thymosin Alpha-1 is 28 residues long, acetylated at the N-terminus and strongly acidic, with a listed mass of about 3108 Da. It is cut from a larger precursor, prothymosin alpha. Research focuses on immune-cell signaling in cell and animal models. See the Thymosin Alpha-1 overview.
Thymosin Beta-4 and TB-500
Thymosin Beta-4 is a 43-residue protein found in most cells, where it binds monomeric actin. TB-500 is a short synthetic peptide modeled on its actin-binding region, so it is a fragment-based material rather than the full protein. See the TB-500 overview.
Telling them apart in the lab
- Mass: about 3108 Da for Thymosin Alpha-1 versus about 889 Da for the TB-500 fragment.
- Charge: Thymosin Alpha-1 is highly acidic; the TB-500 fragment is lysine-rich and basic.
- Termini: both are commonly described with an acetylated N-terminus, which shifts the expected mass by 42 Da.
Terms used in this guide
Related tools and guides
For laboratory research use only. Not for human or veterinary use. This post is general chemistry and literature context and does not describe or endorse any use of Sealed Peptides products.