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Query: UNIPROT:P06889 (
Mol
)
630,302
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
The histamine H2-receptor antagonists have been identified as inhibitors of human liver
aldehyde dehydrogenase
(EC 1.2.1.3) isozymes, E1, E2, and E3. Inhibition was strongest with the E3 isozyme, whose substrates include gamma-aminobutyraldehyde, the aldehyde metabolites of polyamines, and betaine aldehyde. Burimamide, metiamide, cimetidine guanidine, cimetidine, and tiotidine were competitive with aldehyde substrates and noncompetitive with the coenzyme, binding to both the free E3 isozyme and the enzyme-coenzyme binary complex. Cimetidine and tiotidine were the best inhibitors, with Ki values of 1.1 +/- 0.2 microM and 1.0 +/- 0.0 microM, respectively; both are the first ever described potent and selective inhibitors of the E3 isozyme. Examination of the H2-receptor antagonist structures for insight into the moieties accounting for E3 isozyme inhibition pointed to the side-chain polar groups as strongly influencing inhibition, with the cyanoguanidine side chain of cimetidine and tiotidine having the strongest influence. The Ki value of the E3 isozyme for cimetidine was the same as the in vitro dissociation constant for the H2-receptor.
Mol
Pharmacol 1997 Aug
PMID:Cimetidine and other H2-receptor antagonists as inhibitors of human E3 aldehyde dehydrogenase. 927 49
Acetaldehyde is one of the intermediate products of ethanolic fermentation, which can be reduced to ethanol by alcohol dehydrogenase (ADH). Alternatively, acetaldehyde can be oxidized to acetate by
aldehyde dehydrogenase
(
ALDH
) and subsequently converted to acetyl-CoA by acetyl-CoA synthetase (ACS). To study the expression of ALDHs in plants we isolated and characterized a cDNA coding for a putative mitochondrial
ALDH
(TobAldh2A) in Nicotiana tabacum. TobALDH2A shows 54-60% identity at the amino acid level with other ALDHs and shows 76% identity with maize Rf2, a gene involved in restoration of male fertility in cms-T maize. TobAldh2A transcripts and protein were present at high levels in the male and female reproductive tissues. Expression in vegetative tissues was much lower and no induction by anaerobic incubation was observed. This suggests that TobALDH expression is not part of the anaerobic response, but may have another function. The use of specific inhibitors of
ALDH
and the pyruvate dehydrogenase (PDH) complex indicates that
ALDH
activity is important for pollen tube growth, and thus may have a function in biosynthesis or energy production.
Plant
Mol
Biol 1997 Oct
PMID:Aldehyde dehydrogenase in tobacco pollen. 934 59
The pathogenicity of fungal pathogens is presumably dependent on genes that are expressed during infection. In order to isolate such genes from the tomato pathogen Cladosporium fulvum, and to test the hypothesis that starvation-induced genes are also plant induced, a cDNA library was prepared from mycelia grown in a defined medium and then transferred to a starvation medium. The library was then screened with cDNA prepared from starved and replete fungal mycelium. Five unique, differentially expressed cDNAs were isolated from 1,000 clones screened. Northern (RNA) hybridization confirmed that all five were starvation induced. Interestingly, all five were also found to be plant induced. The identity of two of the clones was indicated by partial DNA sequencing as alcohol and
aldehyde dehydrogenase
. The observed correlation between starvation induction and plant induction in discussed.
Mol
Plant Microbe Interact 1997 Dec
PMID:Starvation-induced genes of the tomato pathogen Cladosporium fulvum are also induced during growth in planta. 939 Apr 25
The tissue distribution of the E3 isozyme of human
aldehyde dehydrogenase
has been investigated by three methods: enzyme activity assay employing betaine aldehyde as substrate, Western blotting employing E3 isozyme-specific antibodies, and Northern blotting using a human liver E3 cDNA as probe. All three methods showed that E3 isozyme was universally distributed among all tissues tested. The highest levels of the E3 isozyme activity were found in liver, adrenal gland, and kidney. These same tissues also showed highest levels of the E3 protein via the Western blot. This distribution is consistent with the possible physiological role of E3 isozyme in the synthesis of the osmolyte, betaine, and the neurotransmitter, GABA. Northern blot analysis, however, differed from that of enzyme assay and the Western blot in that it showed highest mRNA levels in skeletal and heart muscles, which had low enzyme activities and E3 protein levels.
Comp Biochem Physiol B Biochem
Mol
Biol 1997 Sep
PMID:Tissue distribution of human aldehyde dehydrogenase E3 (ALDH9): comparison of enzyme activity with E3 protein and mRNA distribution. 941 93
Products of several phase I and II genes transcriptionally activated by ligands of the aryl hydrocarbon receptor (AHR) were quantitated in cutaneous samples isolated from non-tumor-bearing SENCAR or SSIN mice, and animals bearing skin tumors generated in initiation-promotion protocols. The constitutive 7-ethoxyresorufin O-deethylase (EROD) activities in papillomas and squamous cell carcinomas were less than or equal to 37% of the values measured in the adjacent normal cutaneoustissue. Dermal and epidermal EROD specific activities in microsomal samples prepared from both tumor-bearing and non-tumor-bearing mice were elevated 9- to 14- and 43- to 77-fold, respectively, above constitutive levels 16-20 h after a single topical application of 100 nmol of dibenz[a,c]anthracene (DB[a,c]A). EROD specific activities in tumors were maximally elevated two-fold after topical application of DB[a,c]A. Western blot, northern blot, and reverse transcription (RT)-polymerase chain reaction (PCR) analyses confirmed that the EROD measurements reflected cutaneous cytochrome P450 (CYP) 1A1 protein, mature mRNA, and heterogeneous nuclear RNA contents, respectively. Analyses of CYP1A1, CYP1B1, cytosolic
aldehyde dehydrogenase
class 3, and NAD(P)H:menadione oxidoreductase (NMO1) mRNA content by RT-PCR revealed significant increases in all four mRNAs in the normal tissue adjacent to papillomas after exposure to 4 nmol of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) but no increases in the tumors. NMO1 mRNA content in acetone-treated papillomas approached the levels detected in TCDD-treated normal skin. RT-PCR analyses also demonstrated elevated constitutive aryl hydrocarbon receptor nuclear translocator mRNA content (an approximately two-fold increase) in skin tumors. In contrast, AHR mRNA content in the tumors was about 20% of that measured in adjacent normal tissue. Collectively, these studies demonstrated that ligand-induced, AHR-mediated processes are absent in murine skin tumors that develop in initiation-promotion protocols.
Mol
Carcinog 1998 Feb
PMID:Differential induction of Cyp1a1, Cyp1b1, Ahd4, and Nmo1 in murine skin tumors and adjacent normal epidermis by ligands of the aryl hydrocarbon receptor. 949 14
Elevation of activity and mRNA level of a cytosolic
aldehyde dehydrogenase
-1 (ALDH1), which oxidizes aldophosphamide, was previously observed in a cyclophosphamide-resistant murine leukemia cell line. However, changes in other enzyme(s) which may detoxify the drug or produce anti-alkylating agent(s), have not been examined. The human leukemia cell line, K562, was made 30-fold resistant against 4-hydroperoxycyclophosphamide (4HC) by exposing the cells to increasing concentrations of the drug. Resistance against cisplatin was also increased by about 3-fold. Activities of glucose-6-phosphate dehydrogenase (G6PD) and ALDH1 were elevated more than 7-fold in the resistant cells. The mRNA level of the two enzymes was also proportionally elevated. The concentration of reduced glutathione (GSH) was higher in the resistant cells (i.e., 21.1 versus 4.68 nmole per 10(6) cells), while activities of gamma-glutamylcysteine synthetase and glutathione synthetase, and the expressions of other human ALDH genes were not increased in the resistant cells. These findings suggest that the acquired resistance against 4HC is a consequence of transcriptional activation of two genes, i.e., one encoding the G6PD, a major enzyme regenerating anti-alkylating GSH, and the other encoding ALDH1, which has a high activity for oxidation of aldophosphamide derived from 4HC.
Blood Cells
Mol
Dis 1998 Jun
PMID:Enhanced expressions of glucose-6-phosphate dehydrogenase and cytosolic aldehyde dehydrogenase and elevation of reduced glutathione level in cyclophosphamide-resistant human leukemia cells. 971
Methylglyoxal was demonstrated to be a substrate for the isozymes E1, E2 and E3 of human
aldehyde dehydrogenase
. Pyruvate was the product from the oxidation of methylglyoxal by the three isozymes. At pH 7.4 and 25 degrees C, the major and minor components of the E3 isozyme catalyzed the reaction with Vmax of 1.1 and 0.8 mumol NADH min-1 mg-1 protein, respectively, compared to 0.067 and 0.060 mumol NADH min-1 mg-1 protein for the E1 and E2 isozymes, respectively. The E2 isozyme had a K(m) for methylglyoxal of 8.6 microM, the lowest compared to 46 microM for E1 and 586 and 552 microM for the major and minor components of the E3 isozyme, respectively. Both components of the E3 isozyme showed substrate inhibition by methylglyoxal, with Ki values of 2.0 mM for the major component and 12 mM for the minor component at pH 9.0. Substrate inhibition by methylglyoxal was not observed with the E1 and E2 isozymes. Methylglyoxal strongly inhibited the glycolaldehyde activity of the E1 and E2 isozymes. Mixed-type models of inhibition were employed as an approach to calculate the inhibition constants, 44 and 10.6 microM for E1 and E2 isozymes, respectively.
Comp Biochem Physiol B Biochem
Mol
Biol 1998 Apr
PMID:Methylglyoxal as substrate and inhibitor of human aldehyde dehydrogenase: comparison of kinetic properties among the three isozymes. 978 66
The aldA gene (encoding
aldehyde dehydrogenase
) of Escherichia coli is anaerobically repressed by ArcA-P, the phosphorylated response regulator of the ArcB/A two-component signal transduction system. The promoter region of aldA contains two 10-bp sequences (5'-TGTTAATTAA-3') that perfectly match the proposed ArcA-P binding consensus (5'-[A/T]GTTAATTA[A/T]-3'). One consensus sequence is on the coding strand (-13 to -4 from the transcriptional start point), whereas the other is on the template strand (position -2 to -11). In this study we used the aldA promoter to test the validity of the proposed consensus sequence. DNase I protection experiments confirmed the 10-bp sequence to be a strong ArcA-P binding site. Alteration of the wild-type sequence from 5'-TGTTAATTAAC-3' to 5'-TCTTAATTAAG-3' or 5'-TATTAATTAAT-3' by site-directed mutagenesis markedly decreased the in vitro affinity of the promoter region for ArcA-P, and abolished the anaerobic repression of mutant att lambda::phi (aldA'-lacZ) transcriptional reporter constructs. Both the in vitro and in vivo results therefore support the proposed consensus sequence.
Mol
Gen Genet 1999 Feb
PMID:A mutational study of the ArcA-P binding sequences in the aldA promoter of Escherichia coli. 1007 Dec 23
Approximately 10% of Japanese alcoholics develop their disease despite having an inactive form of
aldehyde dehydrogenase
-2 (ALDH2), known as a genetic deterrent of heavy drinking due to adverse reactions after drinking. Such alcoholics are considered to be advantageous in genetic research because they should show reduced heterogeneity and possess genetic factors conferring susceptibility to alcohol dependence. Examination of the -1438 A/G polymorphism of the serotonin 2A (5HT2A) receptor gene in 225 Japanese alcoholics with inactive ALDH2 revealed the presence of significantly more of the G allele than was found in 361 control subjects. The frequency of the G allele in 282 alcoholics with active ALDH2 fell between the G allele frequencies of controls and subjects with inactive ALDH2. These data suggest that although the effect is relatively small, genetic variability in the 5HT2A receptor is involved in the development of alcohol dependence.
Mol
Psychiatry 1999 Jan
PMID:Association of a polymorphism of the 5HT2A receptor gene promoter region with alcohol dependence. 1008 15
Glucocorticoids repressed the polycyclic aromatic hydrocarbon-dependent induction of Class 3
aldehyde dehydrogenase
(ALDH3) enzyme activity and mRNA levels in isolated rat hepatocytes by more than 50 to 80%, with a concentration-dependence consistent with the involvement of the glucocorticoid receptor (GR). No consistent effect on the low basal transcription rate was observed. This effect of glucocorticoids (GC) on polycyclic aromatic hydrocarbon induction was effectively antagonized at the mRNA and protein level by the GR antagonist RU38486. The response was cycloheximide-sensitive, because the protein synthesis inhibitor caused a GC-dependent superinduction of ALDH3 mRNA levels. This suggests that the effects of GC on this gene are complex and both positive and negative gene regulation is possible. The GC-response was recapitulated in HepG2 cells using transient transfection experiments with CAT reporter constructs containing 3.5 kb of 5'-flanking region from ALDH3. This ligand-dependent response was also observed when a chimeric GR (GR DNA-binding domain and peroxisome proliferator-activated receptor ligand-binding domain) was used in place of GR in the presence of the peroxisome proliferator, nafenopin. A putative palindromic glucocorticoid-responsive element exists between -930 and -910 base pairs relative to the transcription start site. If this element was either deleted or mutated, the negative GC-response was completely lost, which suggests that this sequence is responsible, in part, for the negative regulation of the gene. Electrophoretic mobility shift analysis demonstrated that this palindromic glucocorticoid-responsive element is capable of forming a specific DNA-protein complex with human glucocorticoid receptor. In conclusion, the negative regulation of ALDH3 in rat liver is probably mediated through direct GR binding to its canonical responsive element.
Mol
Pharmacol 1999 Apr
PMID:The negative regulation of the rat aldehyde dehydrogenase 3 gene by glucocorticoids: involvement of a single imperfect palindromic glucocorticoid responsive element. 1010 Oct 22
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