Activin A is a member of the transforming growth factor beta family produced by many cell types throughout development. It is a disulfide-linked homodimer (two beta-A chains) that binds to heteromeric complexes of type I (Act RI-A and Act RI-B) and a type II (Act RII-A and Act RII-B) serine-threonine kinase receptor. Activins primarily signal through SMAD2/3 proteins to regulate various functions, including cell proliferation, differentiation, wound healing, apoptosis, and metabolism. Activin A maintains the undifferentiated state of human embryonic stem cells but also facilitates differentiation of human embryonic stem cells into definitive endoderm.

Expression System

Escherichia coli

Sequence

MGLECDGKVNICCKKQFFVSFKDIGWNDWIIAPSGYHANYCEGECPSHIAGTSGSSLSFHSTVINHYRMRGHSPFANLKSCCVPTKLRPMSMLYYDDGQNIIKKDIQNMIVEECGCS with polyhistidine tag at the C-terminus.

Species

Human

Tag

polyhistidine tag at the C-terminus

Endotoxin Level

<0.1 EU per 1 μg of the protein by the LAL method.

Activity

Measure by its ability to induce hemoglobin expression in K562 cells.

The ED50 for this effect is <0.85 ng/mL.

The specific activity of recombinant human Activin A is approximately >1.4 x 10³ IU/mg.

Purity

>95% as determined by SDS-PAGE. Ni-NTA chromatography

Formulation

The protein was lyophilized from a solution containing 0.1% sarkosyl in 1X PBS, pH 8.0.

Reconstitution

Unopened ampoules can be stored at -20°C or -80°C.

Need not spin the ampoule. Open the cap carefully, then dissolve the lyophilized protein with sterile water for a 100 μg/mL concentration or acc ording to the product’s Certificate of

Analysis (CoA). (Note: Need not add carrier* to the initial reconstitution solution).

Rinse the inner side of the ampoule gently and stand for at least 20 minutes at room temperature. (Important Note: Do Not Vortex!)

Use the reconstituted solution immediately or store it by distributing it to aliquots and store at -20 °C. (Important Note: Avoid repeated freeze-thaw cycles)

We recommend diluting the solution to working concentration by using buffers or medium containing a carrier*. (Important Note: Do not dilute the working solution with water, which may cause protein degradation.)

*Carriers: 0.1% BSA or 5% HSA or 10% FBS.