2-Ketoarginine methyltransferase (EC 2.1.1.243, mrsA (gene)) is an enzyme with systematic name S-adenosyl-L-methionine:5-carbamimidamido-2-oxopentanoate S-methyltransferase.^[1] This enzyme catalyses the following chemical reaction

S-adenosyl-L-methionine + 5-guanidino-2-oxopentanoate ${\displaystyle \rightleftharpoons }$ S-adenosyl-L-homocysteine + 5-guanidino-3-methyl-2-oxopentanoate

The enzyme is involved in production of the rare amino acid 3-methylarginine.

• 2-ketoarginine+methyltransferase at the U.S. National Library of Medicine Medical Subject Headings (MeSH)