The diverse family of transforming growth factor –β (TGF-β) proteins are master regulators of tissue homeostasis, controlling cell growth, differentiation, proliferation, and apoptosis. Their deregulated activities are associated with numerous human conditions, including compromised fertility, inflammation, fibrosis, cancers and age-related body wasting. Thus, correcting TGF-β ligand activity is an attractive approach to restore tissue homeostasis. TGF-β based therapeutics, though promising, have poor in vivo stability (thalf life = minutes). The active proteins are derived from large Pro-TGF-β forms that undergo proteolytic maturation. This yields a pro:mature non-covalent complex, with pro and mature (active) domains. The prodomains are removed during commercial preparation, leaving only mature active ligand. However, as prodomains can bind to and shield the active protein, they’re likely to extend the in vivo signaling range of the mature protein. To address this, we aimed to generate a pro:mature complex for a well characterised member of the TGF-β family, activin A. To favour production of the Pro-activin complex, the native cleavage site was enhanced by site-directed mutagenesis. This modification improved the processing of the activin precursor, as evidenced by increased levels of mature activin and a reduction in activin precursors. Pro-activin complexes were successfully isolated from stable HEK-293E cell lines by immunoaffinity using an antibody targeted to the prodomain. Importantly, the purified Pro-activin complex had comparable bioactivity to the commercially available mature preparations, supporting that the prodomain does not perturb activin bioactivity. These studies reveal a new means to generate bioactive TGF-β ligands, with anticipated improved stability in vivo. The next stage is determining the half-life of Pro-activin in an animal model, relative to mature activin. The outcomes of this work will provide a blueprint for generating long-acting TGF-β ligands, which would benefit the treatment of the multitude of human conditions associated with altered TGF-β signaling.