Wu, Shiuan-Woei LinShiuan-Woei LinWuFU-CHUO PENGSyu, Cheng-JieCheng-JieSyuChen, Yu-LianYu-LianChenWang, Andrew H.-J.Andrew H.-J.WangPeng, Fu-ChuoFu-ChuoPeng2018-09-102018-09-102009http://www.scopus.com/inward/record.url?eid=2-s2.0-67349129059&partnerID=MN8TOARShttp://scholars.lib.ntu.edu.tw/handle/123456789/346434Nitrobenzodiazepine (NBDZ) is a sedative-hypnotic drug used in the treatment of anxiety and sleep problems. Overdose of NBDZ may cause severe neurological effects, especially for people in drug abuse or addiction. In the present study, we investigated NBDZ nitroreduction in rat enteric contents and characterized the role of enterobacterial nitroreductase in the reductive pathway. Nitroreduction of flunitrazepam (FZ) was studied in the microsomal membrane fractions of rat liver, jejunum and jejunal microflora using HPLC analysis. In the jejunal microflora, FZ was demonstrated to be significantly reduced to its amino derivative under anaerobic condition. Escherichia coli type I nitroreductase NfsB (EC 1.5.1.34) was found in rat jejunal microflora via PCR technique and Western blotting. The participation of NfsB in FZ nitroreduction was demonstrated from inhibition studies. Kinetic study of the purified recombinant NfsB indicated that nitroreduction of FZ, nitrazepam (NZ) and clonazepam (CZ) are mediated by NfsB, where CZ shows lower kcat/KM ratio than that of the other two. Finally, two other nitroreductases E. cloacae NR (EC 1.6.99.7) and S. typhimurium Cnr were also found to be responsible for FZ nitroreduction. These results provide that the reduction of NBDZ in normal flora is catalyzed by type I nitroreductase NfsB. ? 2009 Elsevier Inc. All rights reserved.application/pdf471350 bytesapplication/pdfEscherichia coli nitroreductase NfsB; Flunitrazepam; NADPH-cytochrome P450 reductase; Nitrobenzodiazepine; Rat jejunal microflora[SDGs]SDG37 aminobenzodiazepine; benzodiazepine derivative; clonazepam; flunitrazepam; nitrazepam; nitrobenzodiazepine; nitroreductase; nitroreductase NfsB; unclassified drug; animal tissue; article; controlled study; drug metabolism; drug structure; Enterobacter cloacae; Enterobacteriaceae; enzyme inhibition; enzyme kinetics; Escherichia coli; high performance liquid chromatography; jejunum; liver microsome; nonhuman; polyacrylamide gel electrophoresis; polymerase chain reaction; priority journal; protein expression; protein purification; rat; reduction; Salmonella typhimurium; statistical analysis; Western blotting; Animals; Benzodiazepines; Biotransformation; Escherichia coli; Escherichia coli Proteins; Flunitrazepam; Intracellular Membranes; Jejunum; Male; Microsomes; Microsomes, Liver; Nitro Compounds; Nitroreductases; Oxidation-Reduction; Rats; Rats, Wistar; Salmonella typhimuriumjournal article10.1016/j.bcp.2009.03.019