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

---

Query: EC:1.1.1.1 (alcohol dehydrogenase)
9,284 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A protein isolated from goat testis cytosol is found to inhibit Na+,K+-ATPase from rat brain microsomes. The inhibitor has been purified by ammonium sulphate precipitation followed by hydroxyapatite column chromatography. The purified fraction appears as a single polypeptide band on 10% SDS-PAGE of approximate molecular mass of 70 kDa. The concentration at which 50% inhibition (I50) occurs is in the nanomolar range. The inhibitor seems to bind Na+,K+-ATPase reversibly at ATP binding site in a competitive manner with ATP, but away from ouabain binding site. It does not affect p-nitrophenyl-phosphatase activity. The inhibitor is found to inhibit the phosphorylation step of the Na+,K+-ATPase. The enhancement of tryptophan fluorescence and changes in CD pattern suggest conformational changes of Na+,K+-ATPase on binding to the inhibitor. Amino acid sequence of the trypsinised fragments show some homology with aldehyde reductase.
...
PMID:Purification, characterization and partial amino acid sequencing of a 70 kD inhibitor protein of Na+,K+-ATPase from goat testis cytosol. 1168 23

Compounds acting as antioxidants to lipids often have a prooxidant effect on DNA or protein. In this study, inactivation of creatine kinase was examined as an indicator of protein damage induced by antioxidative stilbene derivatives, including diethylstilboestrol, resveratrol and tamoxifen, with horseradish peroxidase and hydrogen peroxide (horseradish peroxidase-H2O2). Diethylstilboestrol and resveratrol, but not tamoxifen, rapidly inactivated creatine kinase. Also, creatine kinase in heart homogenate was inactivated by diethylstilboestrol and resveratrol. Tamoxifen, which has no phenolic hydroxyl groups in its structure, was about 10 times less active in protecting lipids and creatine kinase than diethylstilboestrol and resveratrol, suggesting that phenolic hydroxyl groups in diethylstilboestrol and resveratrol of stilbene derivatives are anti- and pro-oxidative. Absorption spectra of these stilbene derivatives rapidly changed during the reaction with horseradish peroxidase-H202. Diethylstilboestrol and resveratrol free radicals emitted electron spin resonance signals and creatine kinase effectively diminished the electron spin resonance signals. These results suggest that free radicals of diethylstilboestrol and resveratrol formed through reaction with horseradish peroxidase-H202 inactivated creatine kinase. Presumably, oxidation of essential cysteine and tryptophan residues lead to inactivation of creatine kinase. Other enzymes, including alcohol dehydrogenase and cholinesterase, were also sharply inhibited by diethylstilboestrol and resveratrol with horseradish peroxidase-H202. Free radicals of diethylstilboestrol and resveratrol seem to mediate between anti- and prooxidative actions.
...
PMID:Inactivation of creatine kinase induced by stilbene derivatives. 1207 28

Evaporation of water from a 1/1 mixture of trehalose and sucrose gives rise to optically clear glasses that are transparent in the UV and visible ranges and do not crystallize when they are prepared at ambient temperatures. Two proteins, liver alcohol dehydrogenase and parvalbumin, and the tryptophan derivative N-acetyl-tryptophanamide were incorporated into the glasses. Infrared spectroscopy of the amide I band reveals that the proteins retain secondary structure in the glass over a temperature range of 20-300K. The amide II band of the protein and the HOH bending band of residual water in the glass shift with temperature changes, consistent with increased H-bonding strength as temperature is lowered. Phosphorescence of tryptophan can be seen from the proteins at room temperature, which shows the immobilization of the protein by the glass and the curbing of oxygen diffusion. It is suggested that using mixed sugars to form glasses is a way to immobilize proteins over a wide temperature range without distortions from solvent crystals.
...
PMID:Mixed trehalose/sucrose glasses used for protein incorporation as studied by infrared and optical spectroscopy. 1213 94

The process of pressure-induced modification of horse liver alcohol dehydrogenase (HLADH) was followed by measuring in situ catalytic activity (up to 250 MPa), intrinsic fluorescence (0.1-600 MPa) and modifications of FTIR spectra (up to 1000 MPa). The tryptophan fluorescence measurements and the kinetic data indicated that the pressure-induced denaturation of HLADH was a process involving several transitions and that the observed transient states have characteristic properties of molten globules. Low pressure (< 100 MPa) induced no important modification in the catalytic efficiency of the enzyme and slight conformational changes, characterized by a small decrease in the centre of spectral mass of the enzyme's intrinsic fluorescence: a native-like state was assumed. Higher pressures (100-400 MPa) induced a strong decrease of HLADH catalytic efficiency and further conformational changes. At 400 MPa, a dimeric molten globule-like state was proposed. Further increase of pressure (400-600 MPa) seemed to induce the dissociation of the dimer leading to a transition from the first dimeric molten globule state to a second monomeric molten globule. The existence of two independent structural domains in HLADH was assumed to explain this transition: these domains were supposed to have different stabilities against high pressure-induced denaturation. FTIR spectroscopy was used to follow the changes in HLADH secondary structures. This technique confirmed that the intermediate states have a low degree of unfolding and that no completely denatured form seemed to be reached, even up to 1000 MPa.
...
PMID:Fluorescence and FTIR study of pressure-induced structural modifications of horse liver alcohol dehydrogenase (HLADH). 1249 82

The catabolism of phenylalanine to 2-phenylethanol and of tryptophan to tryptophol were studied by (13)C NMR spectroscopy and gas chromatography-mass spectrometry. Phenylalanine and tryptophan are first deaminated (to 3-phenylpyruvate and 3-indolepyruvate, respectively) and then decarboxylated. This decarboxylation can be effected by any of Pdc1p, Pdc5p, Pdc6p, or Ydr380wp; Ydl080cp has no role in the catabolism of either amino acid. We also report that in leucine catabolism Ydr380wp is the minor decarboxylase. Hence, all amino acid catabolic pathways studied to date use a subtly different spectrum of decarboxylases from the five-membered family that comprises Pdc1p, Pdc5p, Pdc6p, Ydl080cp, and Ydr380wp. Using strains containing all possible combinations of mutations affecting the seven AAD genes (putative aryl alcohol dehydrogenases), five ADH genes, and SFA1, showed that the final step of amino acid catabolism (conversion of an aldehyde to a long chain or complex alcohol) can be accomplished by any one of the ethanol dehydrogenases (Adh1p, Adh2p, Adh3p, Adh4p, Adh5p) or by Sfa1p (formaldehyde dehydrogenase.)
...
PMID:The catabolism of amino acids to long chain and complex alcohols in Saccharomyces cerevisiae. 1249 63

The binding parameters (binding affinity constant, K and number of binding sites, p) has been determined spectrofluorometrically for chlorpromazine (CPZ) binding to the lens proteins--alphaL-crystallin, betaL-crystallin and gamma-crystallin. The binding affinity constants for CPZ binding to alphaL- and gamma-crystallins are higher than the binding affinity constants for 3betaL-crystallin, although the number of CPZ binding sites for betaL-crystallin is comparatively higher than the number for the other two lens proteins. CPZ causes local conformational changes around the tryptophan moieties of the protein molecules but does not cause any gross conformational change within the protein moieties. Binding of CPZ to alphaL-crystallin does not significantly alter the anti-aggregation properties of the molecular chaperone, alphaL-crystallin against oxidation-induced aggregation of gamma-crystallin at 37 degrees C and thermal aggregation of alcohol dehydrogenase (ADH) at 48 degrees C. Therefore, CPZ induced alteration in chaperone activity of alphaL-crystallin is probably not associated with the formation of cataracts.
...
PMID:Interactions of chlorpromazine with alpha-, beta- and gamma-crystallins. 1253 83

Creatine kinase (CK) was used as a marker molecule to examine the side effects of damage to tissues by mefenamic acid, an effective drug to treat rheumatic and arthritic diseases, with horseradish peroxidase and hydrogen peroxide (HRP-H(2)O(2)). Mefenamic acid inactivated CK during its interaction with HRP-H(2)O(2). Also, diphenylamine and flufenamic acid caused a loss of CK activity, indicating the imino group, not substituent groups, in the phenyl rings have a crucial role in CK inactivation. Rapid change in mefenamic acid spectra was detected, suggesting that mefenamic acid is efficiently oxidized by HRP-H(2)O(2). Peroxidases oxidize xenobiotics to free radicals by a one-electron transfer. However, direct detection of mefenamic acid radicals by electron spin resonance (ESR) was unsuccessful. Reduced glutathione and 5,5-dimethyl-1-pyrroline-1-oxide (DMPO) in the reaction mixture containing mefenamic acid with HRP-H(2)O(2) produced ESR signals consistent with a DMPO-glutathionyl radical adduct. These results suggest that inactivation of CK is probably caused through formation of mefenamic acid radicals. Sulfhydryl groups and tryptophan residues of CK were diminished by mefenamic acid with HRP-H(2)O(2). Other SH enzymes, including alcohol dehydrogenase and glyceraldehyde-3-phosphate dehydrogenase, were very sensitive to mefenamic acid with HRP-H(2)O(2). Inactivation of SH enzymes may explain some deleterious actions of mefenamic acid.
...
PMID:Inactivation of creatine kinase during the interaction of mefenamic acid with horseradish peroxidase and hydrogen peroxide: participation by the mefenamic acid radical. 1259 89

A power-like decay function, characterized by the mean excited-state lifetime and relative variance of lifetime fluctuation around the mean value, was applied in analysis of fluorescence decays measured with the aid of time-correlated single photon counting. We have examined the fluorescence decay, in neutral aqueous medium, of tyrosine (L-tyrosine and N-acetyl-L-tyrosinamide), and of the tyrosine residues in a tryptophan-free protein, the enzyme purine nucleoside phosphorylase from Escherichia coli in a complex with formycin A (an inhibitor), and orthophosphate (a co-substrate). Tryptophan fluorescence decay was examined in neutral aqueous medium for L-tryptophan, N-acetyl-L-tryptophanamide, and for two tryptophan residues in horse liver alcohol dehydrogenase. To detect solvent effect, fluorescence decay of Nz-acetyl-L-tryptophanamide in aqueous medium was compared with that in dioxan. Hitherto, complex fluorescence decays have usually been analyzed with the aid of a multiexponential model, but interpretation of the individual exponential terms (i.e., pre-exponential amplitudes and fluorescence lifetimes), has not been adequately characterized. In such cases the intensity decays were also analyzed in terms of the lifetime distribution as a consequence of an interaction of fluorophore with environment. We show that the power-like decay function, which can be directly obtained from the gamma distribution of fluorescence lifetimes, is simpler and provides good fits to highly complex fluorescence decays as well as to a purely single-exponential decay. Possible interpretation of the power-like model is discussed.
...
PMID:Interpretation of fluorescence decays using a power-like model. 1282 13

The interaction of coenzyme with thermostable homotetrameric NAD(H)-dependent alcohol dehydrogenase from the thermoacidophilic sulphur-dependent crenarchaeon Sulfolobus solfataricus (SsADH) and its N249Y (Asn-249-->Tyr) mutant was studied using the high fluorescence sensitivity of its tryptophan residues Trp-95 and Trp-117 to the binding of coenzyme moieties. Fluorescence quenching studies performed at 25 degrees C show that SsADH exhibits linearity in the NAD(H) binding [the Hill coefficient (h) approximately 1) at pH 9.8 and at moderate ionic strength, in addition to positive co-operativity (h=2.0-2.4) at pH 7.8 and 6.8, and at pH 9.8 in the presence of salt. Furthermore, NADH binding is positively co-operative below 20 degrees C (h approximately 3) and negatively co-operative at 40-50 degrees C (h approximately 0.7), as determined at moderate ionic strength and pH 9.8. Steady-state kinetic measurements show that SsADH displays standard Michaelis-Menten kinetics between 35 and 45 degrees C, but exhibits positive and negative co-operativity for NADH oxidation below (h=3.3 at 20 degrees C) and above (h=0.7 at 70-80 degrees C) this range of temperatures respectively. However, N249Y SsADH displays non-co-operative behaviour in coenzyme binding under the same experimental conditions used for the wild-type enzyme. In loop 270-275 of the coenzyme domain and segments at the interface of dimer A-B, analyses of the wild-type and mutant SsADH structures identified the structural elements involved in the intersubunit communication and suggested a possible structural basis for co-operativity. This is the first report of co-operativity in a tetrameric ADH and of temperature-induced co-operativity in a thermophilic enzyme.
...
PMID:Evidence for co-operativity in coenzyme binding to tetrameric Sulfolobus solfataricus alcohol dehydrogenase and its structural basis: fluorescence, kinetic and structural studies of the wild-type enzyme and non-co-operative N249Y mutant. 1565 78

A combination of hydrogen/deuterium exchange, fluorescence quenching, and kinetic studies was used to acquire experimental evidence for the crystallographically hypothesized increase in local flexibility which occurs in thermophilic NAD(+)-dependent Sulfolobus solfataricus alcohol dehydrogenase (SsADH) upon substitution Asn249Tyr. The substitution, located at the adenine-binding site, proved to decrease the affinity for both coenzyme and substrate, rendering the mutant enzyme 6-fold more active when compared to the wild-type enzyme [Esposito et al. (2003) FEBS Lett. 539, 14-18]. The amide H/D exchange data show that the wild-type and mutant enzymes have similar global flexibility at 22 and 60 degrees C. However, the temperature dependence of the Stern-Volmer constant determined by acrylamide quenching shows that the increase in temperature affects the local flexibility differently, since the K(SV) increment is significantly higher for the wild-type than for the mutant enzyme over the range 18-45 degrees C. Interestingly, the corresponding van't Hoff plot (log K(SV) vs 1/T) proves nonlinear for the apo and holo wild-type and apo mutant enzymes, with a break at approximately 45 degrees C in all three cases due to a conformational change affecting the tryptophan microenvironment experienced by the quencher molecules. The Arrhenius and van't Hoff plots derived from the k(cat) and K(M) thermodependence measured with cyclohexanol and NAD(+) at different temperatures display an abrupt change of slope at 45-50 degrees C. This proves more pronounced in the case of the mutant enzyme compared to the wild-type enzyme due to a conformational change in the structure rather than to an overlapping of two or more rate-limiting reaction steps with different temperature dependencies of their rate constants. Three-dimensional analysis indicates that the observed conformational change induced by temperature is associated with the flexible loops directly involved in the substrate and coenzyme binding.
...
PMID:Temperature-induced conformational change at the catalytic site of Sulfolobus solfataricus alcohol dehydrogenase highlighted by Asn249Tyr substitution. A hydrogen/deuterium exchange, kinetic, and fluorescence quenching study. 1610 Dec 87


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>

---