• Load small G-proteins with a non-hydrolysable GTP analog to lock the GTPase in its active state.
• Study the active conformation of GTPases (e.g., Ras, Rho, Rab)
• Investigate G-protein signaling without turnover to the GDP-bound form

Guanosine 5’-O-(3-thiotriphosphate) tetralithium salt (GTPγS) is supplied as a white powder. Chemical formula C10H12N5O13P3S 4Li. The molecular weight of the trilithium salt GTPγS is 562.98. CAS # 94825-44-2, EC # 305- 606-1.

• Supplied as a lyophilized powder
• When reconstituted, it makes 50 µl of a 20 mM solution

≥85% by HPLC

The biological activity of GTPγS is assessed by its ability to activate small G-proteins such as RhoA or Rac1. In this assay, GTPγS is exchanged into the nucleotide-binding site of the protein in vitro, and the percentage of GTPγS-bound protein is measured via an affinity assay. A functional GTPγS gives ≥5x increase in activated small G-protein compared to the GDP-bound form.