scholarly journals Inactivation of adenosine 5'-triphosphate synthesis and reduced-form nicotinamide adenine dinucleotide dehydrogenase activity in Escherichia coli by near-ultraviolet and violet radiations.

1976 ◽  
Vol 125 (1) ◽  
pp. 111-118 ◽  
Author(s):  
B D Lakchaura ◽  
T Fossum ◽  
J Jagger
1969 ◽  
Vol 42 (3) ◽  
pp. 715-732 ◽  
Author(s):  
Richard W. Hendler ◽  
Amelia H. Burgess ◽  
Raymond Scharff

This paper describes experiments conducted with membranous and soluble fractions obtained from Escherichia coli that had been grown on succinate, malate, or enriched glucose media. Oxidase and dehydrogenase activities were studied with the following substrates: nicotinamide adenine dinucleotide, reduced form (NADH), nicotinamide adenine dinucleotide phosphate, reduced form (NADPH), succinate, malate, isocitrate, glutamate, pyruvate, and α-ketoglutarate. Respiration was virtually insensitive to poisons that are commonly used to inhibit mitochondrial systems, namely, rotenone, antimycin, and azide. Succinate dehydrogenase and NADH, NADPH, and succinate oxidases were primarily membrane-bound whereas malate, isocitrate, and NADH dehydrogenases were predominantly soluble. It was observed that E. coli malate dehydrogenase could be assayed with the dye 2,6-dichlorophenol indophenol, but that porcine malate dehydrogenase activity could not be assayed, even in the presence of E. coli extracts. The characteristics of E. coli NADH dehydrogenase were shown to be markedly different from those of a mammalian enzyme. The enzyme activities for oxidation of Krebs cycle intermediates (malate, succinate, isocitrate) did not appear to be under coordinate genetic control.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Xueying Wang ◽  
Yanbin Feng ◽  
Xiaojia Guo ◽  
Qian Wang ◽  
Siyang Ning ◽  
...  

AbstractNicotinamide adenine dinucleotide (NAD) and its reduced form are indispensable cofactors in life. Diverse NAD mimics have been developed for applications in chemical and biological sciences. Nicotinamide cytosine dinucleotide (NCD) has emerged as a non-natural cofactor to mediate redox transformations, while cells are fed with chemically synthesized NCD. Here, we create NCD synthetase (NcdS) by reprograming the substrate binding pockets of nicotinic acid mononucleotide (NaMN) adenylyltransferase to favor cytidine triphosphate and nicotinamide mononucleotide over their regular substrates ATP and NaMN, respectively. Overexpression of NcdS alone in the model host Escherichia coli facilitated intracellular production of NCD, and higher NCD levels up to 5.0 mM were achieved upon further pathway regulation. Finally, the non-natural cofactor self-sufficiency was confirmed by mediating an NCD-linked metabolic circuit to convert L-malate into D-lactate. NcdS together with NCD-linked enzymes offer unique tools and opportunities for intriguing studies in chemical biology and synthetic biology.


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