title: Purification and characterization of trimethylamine-N-oxide demethylase from jumbo squid (Dosidicus gigas).
abstract: Trimethylamine-N-oxide demethylase (TMAOase) was purified from Jumbo squid (Dosidicus gigas) and characterized in detail herein. The TMAOase was extracted from squid with 20 mM Tris-acetate buffer (pH 7.0) containing 1.0 M NaCl, followed by acid treatment and heat treatment. Then it was purified by deithylaminoethyl-cellulose and Sephacryl S-300 chromatography, subsequently resulting in an 839-fold purification. The molecular mass of the TMAOase was defined to be 17.5 kDa. The optimum pH of the purified TMAOase was 7.0, and its optimum temperature was confirmed to be 55 degrees C. The TMAOase was stable to heat treatment up to 50 degrees C and stable at pH 7.0-9.0. Reducing agents such as DTT, Na2SO3, and NADH were effective at activating TMAOase, and ethylenediaminetetraacetic acid, as well as Mg2+ and Ca2+, could also enhance the activity of TMAOase remarkably, whereas the TMAOase could be significantly inhibited by tea polyphenol, phytic acid and acetic acid. In addition, the TMAOase converted TMAO to dimethylamine and formaldehyde stoichiometrically with a K(m) of 26.2 mM.
authors.affiliation: Department of Food Science and Technology, Ocean University of China, Qingdao, Shandong Province, 266003, People's Republic of China.
authors.forename: Xue-Yan
authors.initials: XY
authors.lastname: Fu
authors.forename: Chang-Hu
authors.initials: CH
authors.lastname: Xue
authors.forename: Ben-Chun
authors.initials: BC
authors.lastname: Miao
authors.forename: Jun-Ni
authors.initials: JN
authors.lastname: Liang
authors.forename: Zhao-Jie
authors.initials: ZJ
authors.lastname: Li
authors.forename: Feng-Xia
authors.initials: FX
authors.lastname: Cui
mesh_terms: D000446:Aldehyde-Lyases / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism; D000818:Animals; D049832:Decapodiformes / Q000201:enzymology*; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008970:Molecular Weight; D013696:Temperature
chemical_list: D004791:Enzyme Inhibitors; D000446:Aldehyde-Lyases; C023188:trimethylamine-oxide aldolase