The enzyme, characterized from the bacterium Streptomyces aureofaciens, is a member of the flavin-dependent halogenase family. The enzyme forms a lysine chloramine intermediate on an internal lysine residue before transferring the chlorine to the substrate. It is stereo-selective for the 4S (natural) isomer of tetracycline. FADH2 is provided by a dedicated EC 220.127.116.11, flavin reductase (NADH).
Dairi, T., Nakano, T., Aisaka, K., Katsumata, R. and Hasegawa, M. Cloning and nucleotide sequence of the gene responsible for chlorination of tetracycline. Biosci. Biotechnol. Biochem.59 (1995) 1099–1106. [DOI] [PMID: 7612997]
Zhu, T., Cheng, X., Liu, Y., Deng, Z. and You, D. Deciphering and engineering of the final step halogenase for improved chlortetracycline biosynthesis in industrial Streptomyces aureofaciens. Metab. Eng.19 (2013) 69–78. [DOI] [PMID: 23800859]