G3BP1 is one of the DNA-unwinding enzymes which prefers partially unwound 3'-tailed substrates and can also unwind partial RNA/DNA and RNA/RNA duplexes in an ATP-dependent fashion. This enzyme is a member of the heterogeneous nuclear RNA-binding proteins and is also an element of the Ras signal transduction pathway. And it cleaves exclusively between cytosine and adenine and cleaves MYC mRNA preferentially at the 3'- UTR. Recombinant human G3BP1 protein, fused to His-tag at C-terminus, was expressed in E.coli and purified by using conventional chromatography techniques.