GDNF

Glial cell line derived neurotrophic factor (GDNF) is a protein promoting the survival of various neuronal subpopulations at different stages of development. These include dopaminergic neurons in midbrain, GDNF stimulates their survival, differentiation, and high-affinity dopamine uptake. The use of GDNF in the treatment of Parkinson's disease and spinal cord injuries has shown promising results. GDNF belongs to the TGF-ß superfamily, it is a homodimeric protein with the familial cysteine-knot structure. Cells expressing GDNF include Sertoli cells, type 1 astrocytes, Schwann cells, neurons, pinealocytes and skeletal muscle cells.

Recombinant human GDNF contains 134 amino acids and a 16 a.a. histidine-based tag for a total length of 150 a.a. and has a predicted molecular mass of 17.2 kDa including his-tag. As a result of glycosylation, the recombinant protein migrates with an apparent molecular mass of 25 kDa in SDS-PAGE.

Produced in the endosperm tissue of barley grain (Hordeum vulgare).

The bioactivity of ISOkine® recombinant human GDNF was assayed by measuring its dose dependent effect on proliferation of rat SH-SY5Y human neuroblastoma cell line.

The ED50 for this effect using GDNF is < 8 ng/ml, corresponding to a specific activity > 1.3 x10e5 U/mg.

We recommend that the optimal concentration for each specific application be determined by an initial dose-response assay. Each batch of ISOkine® growth factor is tested for bioactivity and verified to have comparable activity to a commercial source.

Greater than 95% by SDS-PAGE gel analysis.

Endotoxin level is <0.005ng per µg of ISOkine® product (<0.05EU/µg).

Purified ISOkine® product carries no pyrogenic or pro-inflammatory contaminants, as assayed with monocyte activation test (MAT Assay) using Human 10-plex Cytokine Assay measuring IL-6, TNF-alpha and IL-1 beta induction.

The lyophilized protein, though stable at room temperature for few weeks, is best stored at -20°C. Reconstituted protein should be used immediately or stored in working aliquots at -20°C. Avoid repeated freeze-thaw cycles.

Highly stable as supplied for a maximum of 5 years and a minimum of 12 months from date of receipt (check expiration date specific for each lot# on Certificate of Analysis).

Note: Always centrifuge the vial before opening. It is recommended to reconstitute the lyophilized protein in sterile buffered saline to a concentration of no less than 100 µg/ml. For long term storage of the reconstituted solution it is recommended to add a carrier protein (0.1% HSA or BSA).

PBS pH 7.2, sterile filtered through 0.2 µm filter.