In order to facilitate interpretation of the deazaisoalloxazine system as a valid mechanistic probe of flavoenzyme catalysis, we have examined some of the fundamental chemical properties of this system. The enzymatic synthesis, on a micromole scale, of the flavin coenzyme analogues 5-deazariboflavin 5'-phosphate (deazaFMN) and 5-deazariboflavin 5'-diphosphate, 5' leads to 5'adenosine ester (deazaFAD) has been achieved. This latter synthesis is accomplished with a partially purified FAD synthetase complex (from Brevibacterium ammoniagenes), containing both phosphorylating and adenylylating activities, allowing direct conversion of the riboflavin analogue to the flavin adenine dinucleotide level. The structure of the reduced deazaflavin resulting from enzymatic and chemical reduction is established as the 1,5-dihydrodeazaflavin by proton magnetic resonance. Similarly, the C-5 position of the deazaflavins is demonstrated to be the locus for hydrogen transfer in deazaflavin redox reactions. Preparation of 1,5-dihydrodeazaflavins by sodium borohydride reduction stabilized them to autoxidation (t 1/2 approximately 40 h, 22 degrees C) although dihydrodeazaflavins are rapidly oxidized by other electron acceptors, including riboflavin, phenazine methosulfate, methylene blue, and dichlorophenolindophenol. Mixtures of oxidized and reduced deazaflavins undergo a rapid two-electron disproportionation (k = 22 M-1 S-1 0 degrees C), and oxidized deazaflavins form transient covalent adducts with nitroalkane anions at pH less than 5. Generalized methods for the synthesis of isotopically labeled flavin and deazaflavin coenzymes and their purification by adsorptive chromatography are given.

中文翻译：

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黄素辅酶类似物5-deazariboflavinvin，5-deazariboflavinvin 5'-磷酸盐和5-deazariboflavin 5'-二磷酸盐（5'）的制备，表征和化学性质，导致5'-腺苷酯。

为了促进将脱氮异异恶嗪系统解释为黄素酶催化的有效机理探针，我们已经研究了该系统的一些基本化学性质。黄素辅酶类似物5-deazariboflavin 5'-磷酸（deazaFMN）和5-deazariboflavin 5'-二磷酸的微摩尔规模酶促合成，已实现5'导致5'腺苷酯（deazaFAD）。后者的合成是用部分纯化的FAD合成酶复合物（来自短杆菌属氨化杆菌）完成的，该复合物既具有磷酸化作用，又具有腺苷酸化作用，可将核黄素类似物直接转化为黄素腺嘌呤二核苷酸水平。通过酶和化学还原反应还原的脱氮黄素的结构被确定为1，5-二氢脱氮黄素通过质子磁共振。类似地，证明了脱氮黄素的C-5位置是脱氮黄素氧化还原反应中氢转移的场所。通过硼氢化钠还原制备1,5-二氢脱氮黄素可将其稳定至自氧化（t 1/2约40 h，22摄氏度），尽管二氢脱氮黄素可被其他电子受体迅速氧化，包括核黄素，吩嗪硫酸甲酯，亚甲基蓝和二氯酚吲哚酚。氧化和还原的脱氮核黄素的混合物会经历快速的两电子歧化（k = 22 M-1 S-1 0摄氏度），并且氧化的脱氮核黄素与硝基链烷烃阴离子在pH值小于5的条件下形成瞬时共价加合物。