Purity ~90% (HPLC). Protein arginine methylation is an important posttranslational modification in eukaryotic cells, which has been implicated in RNA processing and trafficking, receptor-mediated signaling, and transcription. CARM1 (coactivator-associated arginine methyltransferase-1) also known as PRMT4 (protein-arginine N-methyltransferase-4) belongs to a family of proteins that catalyzes the methylation of arginine residues. The PRMT proteins are recruited by C-terminal activation domain-2 of the SRC (steroid receptor coactivator) GRIP-1, whereas p300 interacts with activation domain-1 in the C terminus. CARM1 can methylate histone H3 in vitro, and a mutation in the putative S-adenosylmethionine binding domain of CARM1 substantially reduces both methyltransferase and coactivator activities suggesting that coactivator-mediated methylation of proteins in the transcription machinery may contribute to transcriptional regulation. Application: Study enzyme kinetics, and screen small molec