K-Ras4B Mutant Protein: R135A (human recombinant with 6xHis-tag)

On Arrival: 4°C
Before reconstitution, briefly centrifuge to collect the product at the bottom of the tube. The protein should be reconstituted to 5 mg/ml with the addition of 20 ul of Milli-Q water (100 ug size). When reconstituted, the protein will be in the following buffer: 50 mM Tris pH 7.5, 50 mM NaCl, 0.5 mM MgCl₂ 5% (w/v) sucrose and 1% (w/v) dextran. In order to maintain high biological activity of the protein it is strongly recommended that the protein solution be supplemented with DTT to 1 mM final concentration, aliquoted into "experiment sized" amounts, snap frozen in liquid nitrogen and stored a -70C. The protein is stable for six months if stored at -70C. The protein should not be exposed to repeated freeze-thaw cycles. The lyophilized protein is stable at 4C desiccated (< 10% humidity) for one year.

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The biological activity of G12D+I36N K-Ras4B can be determined from the ability of the SOS1 exchange domain (SOS1-ExD) to catalyze the exchange of GDP for GTP on G12D+I36N K-Ras4B. A standard biological assay for monitoring the biological activity of G12D+I36N K-Ras4B is an exchange assay utilizing the 2X Exchange Buffer from the Rho-GEF exchange assay kit (Cat.# BK100) and the human SOS1 GEF domain (Cat.# CS-SOS1).