[EN] A PROCESS FOR THE STEREOSPECIFIC SYNTHESIS OF VITAMIN K2 AND ITS INTERMEDIATES [FR] PROCÉDÉ DE SYNTHÈSE STÉRÉOSPÉCIFIQUE DE LA VITAMINE K2 ET DE SES INTERMÉDIAIRES
摘要:
The present disclosure relates to a novel process for the synthesis of stereospecific compounds of Vitamin K2 group in general and Vitamin K2-7, in particular. It also discloses novel intermediates useful in the synthesis of stereospecific Vitamin K2-7. Compounds of the Vitamin K2 group obtained are crystalline and exhibit well defined melting points.
Electron Transfer Ability from NADH to Menaquinone and from NADPH to Oxygen of Type II NADH Dehydrogenase of<i>Corynebacterium glutamicum</i>
作者:Nawarat NANTAPONG、Asuka OTOFUJI、Catharina T. MIGITA、Osao ADACHI、Hirohide TOYAMA、Kazunobu MATSUSHITA
DOI:10.1271/bbb.69.149
日期:2005.1
from NADH and NADPH to oxygen as well as various artificial quinone analogs at neutral and acidic pHs respectively. The reduction of native quinone of C. glutamicum, menaquinone-2, with this enzyme was observed only with NADH, whereas electron transfer to oxygen was observed more intensively with NADPH. This study provides evidence that C. glutamicum NDH-2 is a source of the reactive oxygen species, superoxide
Structural and Biochemical Evidence for an Enzymatic Quinone Redox Cycle in Escherichia coli
作者:Melanie A. Adams、Zongchao Jia
DOI:10.1074/jbc.m412637200
日期:2005.3
enzymatic reaction. We therefore refer to YgiN as quinol monooxygenase. Modulator of drug activity B is reported to be involved in the protection of cells from reactive oxygen species formed during single electron oxidation and reduction reactions. The enzymatic activities, together with the structural characterization of YgiN, lend evidence to the possible existence of a novel quinone redox cycle in E
generation uses membrane-localized electron transfer chains for ATP synthesis. Formed ATP in turn is consumed for the biosynthesis of cellular building blocks. In contrast, heme cofactor biosynthesis was found driving ATP generation via electron transport after initial ATP consumption. The FMN enzyme protoporphyrinogen IX oxidase (HemG) of Escherichia coli abstracts six electrons from its substrate and transfers
细胞能量生成使用膜定位电子转移链进行 ATP 合成。形成的 ATP 反过来被消耗用于细胞构建块的生物合成。相比之下,发现血红素辅因子生物合成在初始 ATP 消耗后通过电子传递驱动 ATP 生成。大肠杆菌的 FMN 酶原卟啉原 IX 氧化酶 (HemG) 从其底物中提取六个电子,并通过泛醌、细胞色素 bo(3) (Cyo) 和细胞色素 bd (Cyd) 氧化酶将它们转移到氧气中。在厌氧条件下,电子通过甲基萘醌、富马酸 (Frd) 和硝酸还原酶 (Nar) 转移。Cyo、Cyd 和 Nar 有助于推动 ATP 形成的质子动力。从 HemG 通过多种醌到 Cyo、Cyd、Nar 和 Frd 的四个电子传递链在体外从纯化的组分中重组。
Functions of the Membrane-Associated and Cytoplasmic Malate Dehydrogenases in the Citric Acid Cycle of
<i>Escherichia coli</i>
作者:Michel E. van der Rest、Christian Frank、Douwe Molenaar
DOI:10.1128/jb.182.24.6892-6899.2000
日期:2000.12.15
mqo expression. On the contrary, MQO and MDH are active at the same time in E. coli. For Corynebacterium glutamicum, it was found that MQO is the principal enzyme catalyzing the oxidation of malate to oxaloacetate. These observations justified a reinvestigation of the roles of MDH and MQO in the citric acid cycle of E. coli. In this organism, a defined deletion of the mdh gene led to severely decreased
Nitrate, fumarate, and oxygen as electron acceptors for a late step in microbial heme synthesis
作者:N.J. Jacobs、J.M. Jacobs
DOI:10.1016/0005-2728(76)90002-5
日期:1976.10
by addition of nitrate. In contrast, anaerobic protoheme formation from protoporphyrin was not dependent upon addition of nitrate. This was the first demonstration of the ability of nitrate to serve as electronacceptor for this latestep of hemesynthesis. Previous studies with mammalian and yeast mitochondria had indicated an obligatory requirement for molecular oxygen at this step. In confirmation