What makes Fragment 1-4 different from Fragment 17-23?

Fragment 1-4 (Ac-SDKP) comes from the N-terminus of thymosin beta-4 and is mainly studied for anti-fibrotic effects, whereas Fragment 17-23 contains the actin-binding motif tied to cell migration and repair.

Is this fragment naturally found in the body?

Yes. Ac-SDKP is a naturally occurring peptide cleaved from thymosin beta-4 and is normally broken down by angiotensin-converting enzyme (ACE), which is why ACE inhibitors raise its levels.

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Healing & Recovery

Preclinical

TB-500 Fragment (1-4)

Also known as: TB-500 Fragment 1-4, Thymosin Beta-4 Fragment 1-4, TB4 Frag 1-4

TB-500 Fragment 1-4 is the N-terminal tetrapeptide (Ac-SDKP) of thymosin beta-4, studied for anti-fibrotic and tissue-protective effects. This fragment is distinct from the actin-binding region and is associated with regulation of fibrosis and inflammation.

Mechanism of Action

Fragment 1-4 corresponds to N-acetyl-seryl-aspartyl-lysyl-proline (Ac-SDKP), a naturally occurring tetrapeptide released from thymosin beta-4 by prolyl oligopeptidase. Ac-SDKP exerts anti-fibrotic activity by inhibiting TGF-beta and Smad signaling, reducing collagen deposition and fibroblast-to-myofibroblast transition. It also displays anti-inflammatory and pro-angiogenic properties and helps regulate hematopoietic stem cell proliferation.

Half-life: Very short; Ac-SDKP is rapidly degraded by angiotensin-converting enzyme
Administration Routes: subcutaneous
Research Status: Preclinical