Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:1.6.5.3 (complex I)
8,901 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The present study demonstrates that the bovine cardiac sarcolemma possesses an NAD(P)H dehydrogenase activity which is able to oxidize both NADH and NAD(P)H in the presence of vanadate as an electron acceptor. The NADH dehydrogenase activity was significantly higher than the NAD(P)H dehydrogenase activity and both of them were almost completely inhibited by superoxide dismutase and atebrin and markedly reduced by the addition of the protonophore 2,4-dinitrophenol. The incubation of the sarcolemma in the presence of 10(-10), 10(-9), 10(-8) M methionine-enkephalin, a prevalent delta-opioid receptor agonist, or dynorphin A (1-17), a prevalent kappa-receptor agonist, produced a dose-dependent increase in the NAD(P)H dehydrogenase activity, with 10(-10) and 10(-9) M dynorphin A (1-17) more effective than the corresponding doses of methionine-enkephalin. The preincubation of the sarcolemma in the presence of superoxide-dismutase, atebrin or 2,4-dinitrophenol strongly inhibited the opioid-stimulated dehydrogenase activity. The stimulatory action elicited by 10(-8) M methionine-enkephalin or dynorphin A (1-17) was completely antagonized by 10(-8) M naloxone or Mr 1452, respectively, whilst 10(-8) M naloxone exerted only a partially antagonistic action against the effect produced by 10(-8) M dynorphin A (1-17), significantly more accentuated than the action of 10(-8) M Mr 1452 versus the same dose of methionine-enkephalin.
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PMID:Opioids stimulate sarcolemmal NAD(P)H-vanadate dehydrogenase activity. 290 34

The bovine mitochondrial gene products ND2 and ND4, components of NADH dehydrogenase, have been purified from a chloroform/methanol extract of mitochondrial membranes, and the human mitochondrial gene products ND2 and cytochrome b have been obtained by similar procedures. They have been identified by comparison of their amino-terminal protein sequences with those predicted from DNA sequences of bovine and human mitochondrial DNA. All of the proteins have methionine as their amino-terminal residue. In bovine ND2, this residue is encoded by the "universal" isoleucine codon AUA, and the sequences of human cytochrome b and bovine ND2 demonstrate that AUA also encodes methionine in the elongation step of mitochondrial protein synthesis. In human ND2, the amino-terminal methionine is encoded by AUU, which, as in the "universal" genetic code, is also used as an isoleucine codon in elongation. Thus, AUU has a dual coding function which is dependent upon its context.
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PMID:Initiation codons in mammalian mitochondria: differences in genetic code in the organelle. 296 65

Two types of defective mitochondrial DNA molecules with large deletions (5 kbp and 40 kbp) have previously been identified in the stopper mutant, E35, of Neurospora crassa. The junction fragments spanning the deletion endpoints have now been cloned and sequenced, and their sequences compared with those of the corresponding wild-type fragments. We show that both types of defective mitochondrial DNAs result from deletions of sequences flanked by short direct repeats, which are themselves parts of larger inverted repeat sequences. In every case, the short direct repeat sequences consist of a run of pyrimidines in one strand and purines in the other. We also report the sequence of a 2151-bp HindIII fragment, which is deleted in both of the defective mitochondrial DNAs. Besides the previously identified gene for a methionine tRNA, the 2151-bp DNA sequence contains an open reading frame with the potential to code for a hydrophobic protein 583 amino acids long. This hydrophobic protein has three blocks of significant homology with proteins coded by URF2 found in other mitochondrial genomes. Since the mammalian mitochondrial URF2 has recently been shown to code for a subunit of NADH dehydrogenase, part of the DNA sequence missing in the E35 stopper mutant of N. crassa may also code for a subunit of NADH dehydrogenase.
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PMID:The E35 stopper mutant of Neurospora crassa: precise localization of deletion endpoints in mitochondrial DNA and evidence that the deleted DNA codes for a subunit of NADH dehydrogenase. 301 26

The site of synthesis of the iron-sulfur subunits of the flavoprotein and iron-protein fractions of the human respiratory chain NADH dehydrogenase has been investigated to test the possibility that any of them is synthesized in mitochondria. For this purpose, antibodies specific for individual subunits of the bovine enzyme, which cross-reacted with the homologous human subunits in immunoblot assays, were tested against HeLa cell mitochondrial proteins labeled in vivo with [35S]methionine in the absence or presence of inhibitors of mitochondrial or cytoplasmic protein synthesis. The results clearly indicated that all the iron-sulfur subunits of the flavoprotein and iron-protein fractions of human complex I are synthesized in the cytosol and are, therefore, encoded in nuclear genes.
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PMID:The site of synthesis of the iron-sulfur subunits of the flavoprotein and iron-protein fractions of human NADH dehydrogenase. 318 98

The nucleotide sequence of a 3849-bp fragment of starfish mitochondrial genome was determined. The genes for NADH dehydrogenase subunits 3, 4, 5, and COIII, and three kinds of (tRNA(UCNSer), tRNA(His), and tRNA(AGYSer) were identified by comparing with the genes of other animal mitochondria so far elucidated. The gene arrangement of starfish mitochondrial genome was different from those of vertebrate and insect mitochondrial genomes. Comparison of the protein-encoding nucleotide sequences of starfish mitochondria with those of other animal mitochondria suggested a unique genetic code in starfish mitochondrial genome; both AGA and AGG (arginine in the universal code) code for serine, AUA (isoleucine in the universal code but methionine in most mitochondrial systems) for isoleucine, and AAA (lysine) for asparagine. It was also inferred that these AGA and AGG codons are decoded by serine tRNA(AGYSer) originally corresponding to AGC and AGU codons. This situation is similar to the case of Drosophila mitochondrial genome. Variations in the use of AGA and AGG codons were discussed on the basis of the evolution of animals and decoding capacity of various tRNA(AGYSer) species possessing different sizes of the dihydrouridine (D) arm.
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PMID:Unusual genetic codes and a novel gene structure for tRNA(AGYSer) in starfish mitochondrial DNA. 367 36

The effects of an oral neomycin and penicillin regimen on intestinal bacteriology and on morphology and function of the small intestine of mice were investigated. Quantitative and qualitative stool cultures on selective media of the treated animals revealed only growth of yeast organisms. The treated animals developed enlargement of the ceca with fluid contents and watery stools, resembling characteristics of germfree animals. Radioautography with tritiated thymidine revealed an increased epithelial cell migration rate in the mice treated with the antibiotics for 3 to 5 wk. A slight increase in villus height was also noted. The treated male mice showed greater variance than the treated females in epithelial cell migration rates. Histochemical staining reactions showed a decrease in nonspecific esterase and in NADH dehydrogenase activity in the proximal gut of the antibiotic animals. Stains of distal gut and those for acid and alkaline phosphatase, NADPH dehydrogenase, lactic dehydrogenase, and succinic dehydrogenase were similar to the controls. A slight increase in sucrase activity and a slight decrease in lactase activity in the antibiotic animals was observed in contrast to control animals. Germfree mice, however, had greater sucrase and lactase activity. Transport of L-methionine was slightly reduced in the distal segment of the treated animals. Since the direction of these changes is away from the intestinal state observed in germfree animals, they are probably the result of the direct action of the antibiotics on the gut.
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PMID:Effects of neomycin and penicillin administration on mucosal proliferation of the mouse small intestine. With morphological and functional correlations. 438 18

The respiratory NADH dehydrogenase of Escherichia coli has been synthesized in vitro in a coupled transcription--translation system with cloned deoxyribonucleic acid (DNA) as template. The identity of the protein produced was confirmed by paper chromatography and electrophoresis of tryptic peptides. [35S]Methionine-labeled tryptic peptides from the in vitro product were shown to comigrate with authentic methionine-containing tryptic peptides from the purified enzyme. Using a transcription-translation system derived from an ndh mutant, it was shown that the enzyme produced in vitro was incorporated into membrane vesicles of the mutant to give functional, cyanide-sensitive NADH oxidase activity. Radiochemical N-terminal sequencing of the synthesized NADH dehydrogenase showed that the product was a mixture of three different species, with N-formylmethionine, methionine, or threonine at the N terminus. The results indicated that only partial N-terminal processing was occurring in vitro and that the first residue of the unprocessed NADH dehydrogenase is N-formylmethionine. Since DNA sequencing has shown that this residue is encoded by UUG [Young, I. G., Rogers, B. L., Campbell, H. D., Jaworowski, A., & Shaw, D. C. (1981) Eur. J. Biochem. (in press)], this work verifies the role of UUG as a normal initiation codon.
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PMID:In vitro synthesis of the respiratory NADH dehydrogenase of Escherichia coli. Role of UUG as initiation codon. 702 92

The nucleotide sequence of a 27,588-bp region of rice mitochondrial DNA was determined. This sequence contains putative genes that encode initiator methionine tRNA (trnfM), subunits III (nad3) and IV (nad4) of the NADH dehydrogenase complex, and ribosomal proteins S3 (rps3), S12 (rps12) and L16 (rpl16). An open reading frame that contains sequences homologous to parts of rps2 and atpA is also present. In addition to these regions, there are many short sequences with homology to fragments of mitochondrial DNAs from rice or other plants. These sequences may be remnants of multiple rearrangements of the genome and their presence seems to explain, in part, the large sizes of the mitochondrial genomes of higher plants.
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PMID:Nucleotide sequence of a 28-kbp portion of rice mitochondrial DNA: the existence of many sequences that correspond to parts of mitochondrial genes in intergenic regions. 754 79

Two distinct loci for the 24-kDa subunit of the mitochondrial NADH:ubiquinone oxidoreductase (complex I of the respiratory chain) were detected in the human genome: a transcribed gene from chromosome 18 and an inactive locus on chromosome 19. Cosmid clones containing the functional gene (NDUFV2) and the pseudogene (NDUFV2P1) were isolated. The NDUFV2 gene spans approximately 20 kb and contains 8 exons. Refined mapping of both NDUFV2 genes by FISH resulted in an assignment of the NDUFV2 gene to 18p11.2-p11.31 and of the NDUFV2P1 gene to 19q13.3-qter. The nucleotide sequence of the NDUFV2P1 pseudogene differs from the cDNA sequence by the lack of the methionine initiator codon, an additional 165 bp of the first intron sequence, and a 1-nucleotide deletion.
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PMID:Molecular cloning and characterization of the active human mitochondrial NADH:ubiquinone oxidoreductase 24-kDa gene (NDUFV2) and its pseudogene. 760 68

We have sequenced a region (7,376-bp) of the mitochondrial (mt) DNA (54 kb) of the cellular slime mold, Dictyostelium discoideum. From the DNA and amino-acid sequence comparisons with known sequences, genes for ATPase subunit 9 (ATP9), cytochrome b (CYTB), NADH dehydrogenase subunits 1, 3 and 6 (ND1, ND3 and ND6), small subunit rRNA (SSU rRNA) and seven tRNAs (Arg, Asn, Cys, Lys, f-Met, Met and Pro) have been identified. The sequenced region of the mtDNA has a high average A + T-content (70.8%). The A + T-content of protein-genes (73.6%) is considerably higher than that of RNA genes (61.3%). Even with the strong AT-bias, the genetic code employed is most probably the universal one. All seven tRNAs are able to form typical clover leaf structures. The molecular phylogenetic trees of CYTB and SSU rRNA suggest that D. discoideum is closer to green plants than to animals and fungi.
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PMID:Codon usage, genetic code and phylogeny of Dictyostelium discoideum mitochondrial DNA as deduced from a 7.3-kb region. 773 10


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