Recombinant BLM Helicase Enzyme, Active, Human

Active, human Bloom Syndrome Helicase enzyme (aa 630-1290), His-tagged protein expressed and purified from Baculovirus-infected insect cells. The enzyme has been thoroughly validated with the Transcreener ADP2 Kinase Assay Kits. For specific activity, please refer to the Certificate of Analysis for each individual enzyme lot. Purity is >85% in a composition of 50 mM Tris-HCl pH 8.0, 500 mM NaCl, 5% glycerol. Currently, BLM Helicase enzyme is used with the Transcreener assay at a concentration between 150 pM in a 10 µL reaction. Protein Function: ATP-dependent DNA helicase that unwinds double-stranded (ds)DNA in a 3'-5' direction (PubMed:24816114, PubMed:25901030, PubMed:9388193, PubMed:9765292). Participates in DNA replication and repair (PubMed:12019152, PubMed:21325134, PubMed:23509288, PubMed:34606619). Involved in 5'-end resection of DNA during double-strand break (DSB) repair: unwinds DNA and recruits DNA2 which mediates the cleavage of 5'-ssDNA (PubMed:21325134). Stimulates DNA 4-way junction branch migration and DNA Holliday junction dissolution (PubMed:25901030). Binds single-stranded DNA (ssDNA), forked duplex DNA and Holliday junction DNA (PubMed:20639533, PubMed:24257077, PubMed:25901030). Unwinds G-quadruplex DNA, unwinding occurs in the 3'-5' direction and requires a 3' single-stranded end of at least 7 nucleotides (PubMed:18426915, PubMed:9765292). Helicase activity is higher on G-quadruplex substrates than on duplex DNA substrates (PubMed:9765292). Telomeres, immunoglobulin heavy chain switch regions and rDNA are notably G-rich, formation of G-quadruplex DNA would block DNA replication and transcription (PubMed:18426915, PubMed:9765292). Negatively regulates sister chromatid exchange (SCE) (PubMed:25901030). Recruited by the KHDC3L-OOEP scaffold to DNA replication forks where it is retained by TRIM25 ubiquitination, it thereby promotes the restart of stalled replication forks (By similarity) , (Microbial infection) Eliminates nuclear HIV-1 cDNA, thereby suppressing immune sensing and proviral hyper-integration [The Uniprot Consortium]