Swiegers Jan H, Vaz Frédéric M, Pretorius Isak S, Wanders Ronald J A, Bauer Florian F
Institute for Wine Biotechnology, Department of Viticulture and Oenology, Stellenbosch University, 7600, South Africa.
FEMS Microbiol Lett. 2002 Apr 23;210(1):19-23. doi: 10.1111/j.1574-6968.2002.tb11154.x.
The biosynthesis of L-carnitine in eukaryotic organisms was first elucidated in the ascomycete Neurospora crassa. The first step of the pathway is catalysed by epsilon-N-trimethyllysine hydroxylase (TMLH), which converts epsilon-N-trimethyllysine into beta-hydroxy-N-epsilon-trimethyllysine in a reaction dependent on alpha-ketoglutarate, Fe2+ and oxygen. Here we report on the cloning of the N. crassa TMLH cDNA and its functional expression in Saccharomyces cerevisiae. The TMLH cDNA contains an open reading frame of 1413 base pairs encoding a predicted polypeptide of 471 amino acids. The Michaelis-Menten constants of the heterologously expressed enzyme were determined for epsilon-N-trimethyllysine, alpha-ketoglutarate, Fe2+ and correspond to 0.33 mM, 133 microM and 46 microM, respectively.
真核生物中L-肉碱的生物合成最初是在子囊菌粗糙脉孢菌中阐明的。该途径的第一步由ε-N-三甲基赖氨酸羟化酶（TMLH）催化，它在依赖于α-酮戊二酸、Fe2+和氧气的反应中将ε-N-三甲基赖氨酸转化为β-羟基-N-ε-三甲基赖氨酸。在此，我们报道了粗糙脉孢菌TMLH cDNA的克隆及其在酿酒酵母中的功能表达。TMLH cDNA包含一个1413个碱基对的开放阅读框，编码一个预测的471个氨基酸的多肽。测定了异源表达酶对ε-N-三甲基赖氨酸、α-酮戊二酸、Fe2+的米氏常数，分别对应于0.33 mM、133 μM和46 μM。
