Hill R E, Himmeldirk K, Kennedy I A, Pauloski R M, Sayer B G, Wolf E, Spenser I D
Department of Pathology, McMaster University, Hamilton, Ontario L8S 4M1, Canada.
J Biol Chem. 1996 Nov 29;271(48):30426-35. doi: 10.1074/jbc.271.48.30426.
It is shown by incorporation experiments with 13C bond-labeled substrates, followed by analysis by means of 13C NMR spectroscopy, that two compounds, 1-deoxy-D-xylulose (12) and 4-hydroxy-L-threonine (), serve as precursors of pyridoxol (vitamin B6) (1) in Escherichia coli. Together, these two compounds account for the entire C8N skeleton of the vitamin. 1-Deoxy-D-xylulose supplies the intact C5 unit, C-2',2,3,4,4' of pyridoxol. 4-Hydroxy-L-threonine undergoes decarboxylation in supplying the intact C3N unit, N-1,C-6,5,5'. Both precursors are ultimately derived from glucose. The C5 unit of pyridoxol that is derived from 1-deoxy-D-xylulose originates by union of a triose phosphate (yielding C-3,4,4') with pyruvic acid (which decarboxylates to yield C-2',2). D-Erythroate (11) enters the C3 unit, C-6,5,5', and is therefore an intermediate on the route from glucose into 4-hydroxy-L-threonine.
通过用(^{13}C)键标记的底物进行掺入实验，随后借助(^{13}C)核磁共振光谱进行分析表明，两种化合物，1-脱氧-D-木酮糖（12）和4-羟基-L-苏氨酸（），是大肠杆菌中吡哆醇（维生素B6）（1）的前体。这两种化合物共同构成了维生素的整个C8N骨架。1-脱氧-D-木酮糖提供了完整的C5单元，即吡哆醇的C-2'，2，3，4，4'。4-羟基-L-苏氨酸在提供完整的C3N单元N-1，C-6，5，5'时发生脱羧反应。两种前体最终都来源于葡萄糖。吡哆醇中源自1-脱氧-D-木酮糖的C5单元是由磷酸丙糖（产生C-3，4，4'）与丙酮酸（脱羧产生C-2'，2）结合而成。D-赤藓糖（11）进入C3单元C-6，5，5'，因此是从葡萄糖到4-羟基-L-苏氨酸途径中的中间体。
