Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:1.6.99.5 (NADH dehydrogenase)
 2,135 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

1. The reconstitution of oxidase activity in cell-free extracts of a mutant of Escherichia coli K12Ymel, that require 5-aminolaevulinic acid for growth on non-fermentable carbon sources, is described. 2. The reconstitution is dependent on haematin or a haem extract from a prototrophic strain of E. coli, and the product of the reaction has been identified as NADH-reducible cytochrome b. 3. The requirement for haematin cannot be replaced by four other porphyrins. Coproporphyrin III does not inhibit the haematin-dependent reconstitution, mesoporphyrin IX and protoporphyrin IX apparently compete with haematin for a binding site on the cytochrome apoprotein(s) and deuteroporphyrin IX binds to cytochrome apoprotein(s) and cannot be subsequently replaced by haematin. 4. The properties of electron-transport particles from cell-free extracts of the mutant strain, grown aerobically in the presence or absence of 5-aminolaevulinic acid, are described. In the absence of 5-aminolaevulinic acid no detectable cytochromes are produced, and oxidase activities are lowered but there is no apparent effect on the activities of the NADH dehydrogenase and d-lactate dehydrogenase. 5. The reconstitution of oxidase activity by electron-transport particles from cells grown in the absence of 5-aminolaevulinic acid requires ATP and haematin, and the product of the reaction was identified as NADH-reducible cytochrome b. 6. It is concluded that the cytochrome apoproteins are synthesized and incorporated into the cytoplasmic membrane of E. coli in the absence of haem synthesis. The subsequent reconstitution of functional cytochrome(s) requires protohaem, but the nature of the side chain on the 2 and 4 positions of the porphyrin appears to be important.
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PMID:The reconstitution of oxidase activity in membranes derived from a 5-aminolaevulinic acid-requiring mutant of Escherichia coli. 415 Jun 52

Synthesis of the membrane-bound, flavin-linked D-lactate dehydrogenase of Escherichia coli has been studied by using a recombinant plasmid containing the dld gene [Young, I. G., Jaworowski, A., & Poulis, M. (1982) Biochemistry (following paper in this issue)]. Expression of the cloned dld gene was achieved either in vivo with transformed minicells or in vitro with a fractionated transcription/translation system. In both instances, a product is observed that is specifically immunoprecipitated by gamma-globulin prepared against the purified enzyme and comigrates with authentic D-lactate dehydrogenase on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Furthermore, the product is catalytically active and binds to membrane vesicles during or after synthesis. Thus, it seems likely that the protein is synthesized in mature form and binds to the membrane without a leader peptide sequence. Interestingly, addition of flavin adenine dinucleotide to the in vitro reaction mixtures causes a 2-fold increase in the synthesis of the enzyme, suggesting that the cofactor plays a regulatory role in the synthesis of the apoprotein. Finally, L factor, a protein involved in regulation of protein elongation, has an inhibitory effect on the expression of the dld gene and a stimulatory effect on the expression of the ndh gene (encoding NADH dehydrogenase).
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PMID:In vitro synthesis of the membrane-bound D-lactate dehydrogenase of Escherichia coli. 704 93