Diaminopelargonic acid aminotransferase (DAPA AT), which is involved in biotin biosynthesis, catalyzes the transamination of 8-amino-7-oxonona-noic acid (KAPA) using S-adenosyl-l-methionine (AdoMet) as amino tuberculosisDAPA AT, a potential therapeutic tar-get, has been overproduced inEscherichia coliand purified to homogeneity using a single efficient step on a nickel-affinity column.