Modification of aspartate before its condensation with dihydroxyacetone phosphate during quinolinic acid formation in Escherichia coli.
نویسندگان
چکیده
A crude enzyme preparation from a nadA mutant of Escherichia coli was used to catalyze the conversion of [14C]aspartic acid into a precursor of quinolinic acid, a key intermediate in the biosynthesis of nicotinamide adenine dinucleotide.
منابع مشابه
L-Aspartate oxidase, a newly discovered enzyme of Escherichia coli, is the B protein of quinolinate synthetase.
In Escherichia coli, quinolinic acid, a precursor of NAD+, is synthesized from L-aspartate and dihydroxyacetone phosphate. This synthesis requires two enzymes, a FAD-containing "B protein" and an "A protein." The B protein has been purified 500-fold from E. coli cells. The enzyme behaves as an L-aspartate oxidase. In the absence of A protein, it converts L-aspartate to oxaloacetate. To our know...
متن کاملEvidence for an intermediate in quinolinate biosynthesis in Escherichia coli.
Evidence for the formation of an unstable intermediate in the synthesis of quinolinate from aspartate and dihydroxyacetone phosphate by Escherichia coli was obtained using toluenized cells of nadA and nadB mutants of this organism and partially purified A and B proteins in dialysis and membrane cone experiments. The results of these experiments indicate that the nadB gene product forms an unsta...
متن کاملStudies on the de novo Biosynthesis of NAD in Escherichia coli
Quinolinic acid (pyridine 2,3-dicarboxylic acid) which is an immediate precursor of the pyridine nucleotides, is synthesised from L-aspartate and dihydroxyacetone phosphate in Escherichia coli. Extracts from certain nadB mutants complement the extracts prepared from all nadA mutants for the enzymic synthesis of quinolinate. Using the complementation assay, the quinolinate synthetase B protein h...
متن کاملQuinolinate synthetase, an iron-sulfur enzyme in NAD biosynthesis.
Nicotinamide adenine dinucleotide (NAD) plays a crucial role as a cofactor in numerous essential redox biological reactions. NAD derives from quinolinic acid which is synthesized in Escherichia coli from L-aspartate and dihydroxyacetone phosphate (DHAP) as the result of the concerted action of two enzymes, L-aspartate oxidase (NadB) and quinolinate synthetase (NadA). We report here the characte...
متن کاملAnalysis of amino acid motifs diagnostic for the sn-glycerol-3-phosphate acyltransferase reaction.
Alignment of amino acid sequences from various acyltransferases [sn-glycerol-3-phosphate acyltransferase (GPAT), lysophosphatidic acid acyltransferase (LPAAT), acyl-CoA:dihydroxyacetone-phosphate acyltransferase (DHAPAT), 2-acylglycerophosphatidylethanolamine acyltransferase (LPEAT)] reveals four regions of strong homology, which we have labeled blocks I-IV. The consensus sequence for each cons...
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ورودعنوان ژورنال:
- Journal of bacteriology
دوره 141 2 شماره
صفحات -
تاریخ انتشار 1980