SF3B14, also known as SAP14, is a 125 amino acid nuclear protein that is a component of the splicing factor 3b complex. Splicing factor 3b associates with both the U2 and U11/U12 small nuclear ribonucleoprotein complexes (U2 snRNP) of spliceosomes. Required for the splicing of pre-mRNA, SF3B14 enters the spliceosome and associates with the pre-mRNA branch site facilitating the interaction of snRNP with the branch sites of U2 and U12 of the 17S U2 and the 18S U11/U12 snRNP complex. Recombinant human SF3B14 protein, fused to His-tag at N-terminus, was expressed in E.coli and purified by using conventional chromatography techniques.