Mukherjee Tathagata, Kinsland Cynthia, Begley Tadhg P
Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853, USA.
Bioorg Chem. 2007 Dec;35(6):458-64. doi: 10.1016/j.bioorg.2007.07.003. Epub 2007 Sep 14.
The function of the mlr6793 gene from Mesorhizobium loti MAFF303099 has been identified. This gene encodes 4-pyridoxic acid dehydrogenase, an enzyme involved in the catabolism of PLP (Vitamin B6). This enzyme was overexpressed in Escherichia coli and characterized. 4-Pyridoxic acid dehydrogenase is a 33kDa protein that catalyzes the four electron oxidation of 4-pyridoxic acid to 3-hydroxy-2-methylpyridine-4,5-dicarboxylate, using nicotinamide adenine dinucleotide as a cofactor. The k cat for NADH production is 0.01s(-1). The KM values for 4-pyridoxic acid and NAD are 5.8 and 6.6microM, respectively.
已鉴定出来自百脉根中生根瘤菌MAFF303099的mlr6793基因的功能。该基因编码4-吡哆酸脱氢酶，这是一种参与PLP（维生素B6）分解代谢的酶。该酶在大肠杆菌中过表达并进行了特性分析。4-吡哆酸脱氢酶是一种33kDa的蛋白质，它以烟酰胺腺嘌呤二核苷酸作为辅因子，催化4-吡哆酸的四电子氧化反应生成3-羟基-2-甲基吡啶-4,5-二羧酸。生成NADH的催化常数k cat为0.01s(-1)。4-吡哆酸和NAD的米氏常数KM分别为5.8和6.6μM。
