TB-500 (Thymosin Beta-4) mastery course
Unit 2 of 12

The molecule and its structure

Thymosin beta-4 has no fixed shape in solution. It is an intrinsically disordered chain of 43 amino acids that only fol…

A floppy 43-residue chain that grips actin

Thymosin beta-4 has no fixed shape in solution. It is an intrinsically disordered chain of 43 amino acids that only folds when it docks onto a partner, and its most important partner is actin. The conserved LKKTET motif in the middle does the gripping.

This unit walks the sequence, the disorder, and how the whole peptide wraps an actin monomer, plus what separates trial-grade thymosin beta-4 from a gray-market TB-500 vial.

Key terms

The 43-amino-acid sequence


How it wraps an actin monomer


A protein with no fixed shape


Trial-grade Tβ4 versus gray-market TB-500


The active fragment and the QC problem