PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Benzophenones”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 361 records · Page 20Linked to original sources
PubMed1982

[Photoallergic contact dermatitis by benzophenone containing sunscreening preparations].

The case of a 42-year-old woman with sunlight-provoked eczematous eruptions recurrent over several years is reported. Photopatch-testing with cosmetic products and sunscreen preparations used by the patient as well as the active ingredient of the sunscreen formulations revealed photosensitivity to the UV-blocking agent 2-hydroxy-4-methoxybenzophenone. The active wavelengths were shown to be in the UV-A range.

Adult↗
PubMed1993

Photoaffinity labeling of ribulose-1,5-bisphosphate carboxylase/oxygenase activase with ATP gamma-benzophenone. Identification of the ATP gamma-phosphate binding domain.

The phosphate-binding domain of the ATP-binding site of tobacco Rubisco (ribulose-1,5-bisphosphate carboxylase/oxygenase) activase was elucidated by photo-affinity labeling with a monoanhydride of ADP with N-(4-(benzoyl)phenylmethyl)phosphoramide ([gamma-32P]ATP gamma BP). Covalent incorporation of [gamma-32P]ATP gamma BP into the 42-kDa Rubisco activase subunit was dependent upon irradiation with ultraviolet light. Photolabelling of Rubisco activase with ATP gamma BP exhibited saturation kinetics; the apparent Kd for photolabeling was 5 microM. Two lines of evidence showed that ATP gamma BP modified Rubisco activase at the ATP-binding domain. First, physiological concentrations of ATP and ADP afforded complete protection against photolabeling of Rubisco activase by ATP gamma BP. Second, photolysis of Rubisco activase in the presence of ATP gamma BP decreased both the ATPase and the Rubisco activating activities. Inactivation of enzyme activity was dependent on ATP gamma BP concentration and could be prevented by including ADP during photolabeling. The region of Rubisco activase that was modified by ATP gamma BP was identified by isolating photolabeled peptides. Sequence analysis showed that ATP gamma BP modified Rubisco activase in two distinct regions; one region, S117-A136, is adjacent to the P-loop and the other region, V223-T234, exhibits homology to a region of adenylate kinase that ligates the essential metal ion. Photolabeling of these two regions of Rubisco activase was consistent with modification of the ATP gamma-phosphate-binding domain of Rubisco activase with ATP gamma BP.

Adenosine Diphosphate↗
PubMed1993

[Antiarrhythmia active amidinohydrazone substituted benzophenones. 5. The stability of (Z)-2-amino-5-chlorobenzophenone amidinohydrazone acetate in solution].

The aqueous solution of the title compound can be used for injection for one year if it is stored at room temperature and under light protection. Under these conditions 8% of the E-isomer are produced. The reaction is reversible at day light. Red coloured products of decomposition are formed by long lasting influence of light. At higher temperatures or at sterilisation several products of decomposition are formed which structure is elucidated. For these decomposition a scheme is proposed.

Anti-Arrhythmia Agents↗
PubMed1976

[New results on migration behavior of benzophenone-based UV absorbents from polyolefins in foods].

The authors deal with the migration behaviour of bezophenone-based ultraviolet absorbents for commodities of low-pressure polyethylene, high-pressure polyethlene, polypropylene and polystyrene. These ultraviolet-absorbent-stabilized plastics (up to 0.5% of ultraviolet absorbent) show a very slight tendency of the light stabilizers towards migration into aqueous, acid or dilute alcoholic foods. Very high migration values are obtained for sunflower oil, Fettsimulans HB 307 or 50% ethanol. The amount of 2-hydroxy-4-octoxybenzophenone which migrates into fat-free foods is only a fraction of the maximum daily dose; a risk to the consumers' health might thus be excluded. In fat-containing foods, the maximum daily dose is also not reached, but the single migration value is higher than the limit value (100 p.p.m.) for total migration. Consequently, the above ultraviolet absorbents should not be used for the ultraviolet stabilization of plastics designed for packing these products. An evaluation of the safety of ultraviolet absorbents of the Dastib type will be possible only if sufficient toxicological data are available.

Alcoholic Beverages↗
PubMed1983

Formation of benzophenone and alpha, alpha-diarylacetophenone metabolites of the antiestrogen nitromiphene (CI628) in the presence of rat cecal contents.

Incubation of the nonsteroidal antiestrogen nitromiphene (CI628) with rat cecal content suspension under aerobic or anaerobic conditions resulted in extensive biotransformation, yielding three metabolites, as determined by thin-layer chromatography. These metabolites were not recovered from incubation mixtures containing previously frozen suspension, and recoveries were decreased (that of nitromiphene was increased) when incubations were carried out in the presence of 2mM EDTA. Spectral and chromatographic comparison of two of the purified metabolites resulted in their structural characterization, as p-[beta(N-pyrrolidinyl)ethoxy]p'-methoxybenzophenone, and a similarly substituted alpha, alpha-diphenyl-acetophenone. These metabolites are, in turn, due formally to ethylenic bond cleavage and nitro group reduction/hydrolysis of nitromiphene.

Aerobiosis↗
PubMed1996

Photoaffinity labeling of rat steroid 5 alpha-reductase (isozyme-1) by a benzophenone derivative of a 4-methyl-4-azasteroid.

[1,2-3H]N-4(Benzylbenzoyl)-3-oxo-4-aza-4-methyl-5 alpha-androstane-17 beta-carboxamide ([3H]-4MABP) has been synthesized as a photoaffinity probe of the steroid-binding domain of rat steroid 5 alpha-reductase isozyme-1 (5 alpha R-1). Reversible binding of the probe to 5 alpha R-1 in microsomal preparations yielded a reversible dissociation constant (Kd) of -3 nM, whereas inhibition experiments indicated that the probe had a 50% inhibition concentration of 4.4 nM and was a competitive inhibitor of the enzyme (Ki approximately 3 nM) with respect to testosterone. SDS-PAGE analysis of microsomal, detergent-solubilized, and (6.5%) polyethylene glycol-precipitated fractions of 5 alpha R-I photolyzed with [3H]4MABP in the presence of NADPH showed that the radioactivity was incorporated into a single protein band with a mass of 26 kDa (apparent molecular weight of 5 alpha R-1). UV photolysis was accompanied by an irreversible loss in enzyme activity, consistent with its covalent modification. Increasing the time of UV irradiation and concentration of [3H]4MABP indicated that the half-life and apparent Kd for its photo insertion were approximately 3 min and 7.5 nM, respectively. Photolysis in the presence of a 20-fold excess of N,N-diethyl-4-aza-4-methyl-3-oxo-5 alpha-androstane-17 beta-carboxamide or the 3-carboxysteroid SKF-105111 resulted in partial protection of 5 alpha R-1 from the probe, whereas minimal incorporation of radioactivity was observed in the absence of NADPH or in the presence of NADP+. The results indicate that [3H]4MABP is an effective probe of the steroid (D-ring) binding domain of 5 alpha R-1.

3-Oxo-5-alpha-Steroid 4-Dehydrogenase↗
PubMed2005

Photoaffinity labeling of P450Cam by an imidazole-tethered benzophenone probe.

[(3)H]4-Benzoyl-N-[2-(imidazole-4-yl)ethyl]benzamide ([(3)H]HBP) was synthesized and used to photoaffinity label P450(Cam). The imidazole moiety of HBP anchors the compound in the P450(Cam) active site by coordination of the heme iron, thereby insuring that covalent modification occurs in the active site. Additionally, the imidazole anchor provides a known binding orientation of HBP to P450(Cam) from which conclusions about enzyme structure can be drawn based upon the locations of photoadducted residues. Two sites of adduction were identified by MS analysis of digested, photoaffinity labeled P450(Cam). Photoaffinity labeling experiments in the presence of the type II competitive inhibitor, 1-phenylimidazole, were used to assess the specificity of the photoadducts characterized. One adduct was located at Met103 on the flexible B'/C loop region of P450(Cam). The other adduct was localized on the C-helix at Met121. The implications of these data are discussed.

Amino Acid Sequence↗
PubMed1990

Phenyl azide substituted and benzophenone-substituted phosphonamides of 7-methylguanosine 5'-triphosphate as photoaffinity probes for protein synthesis initiation factor eIF-4E and a proteolytic fragment containing the cap-binding site.

Three photoactive derivatives of the 7-methylguanosine-containing cap of eukaryotic mRNA were used to investigate protein synthesis initiation factor eIF-4E from human erythrocytes and rabbit reticulocytes. Sensitive and specific labeling of eIF-4E was observed with the previously described probe, [gamma-32P]-gamma-[[(4-benzoylphenyl)methyl]amido]-7-methyl-GTP [Blaas et al. (1982) Virology 116, 339; abbreviated [32P]BPM]. A second probe was synthesized that was an azidophenyltyrosine derivative of m7GTP [( 125I]APTM), the monoanhydride of m7GDP with [125I]-N-(4-azidophenyl)-2-(phosphoramido)-3-(4-hydroxy-3-iodop hen yl) propionamide. This probe allowed rapid and quantitative introduction of radioactivity in the last rather than the first step of synthesis and placed the radioactive label on the protein-proximal side of the weak P-N bond. A dissociation constant of 6.9 microM was determined for [125I]APTM, which is comparable to the published values for m7GTP. m7GTP and APTM were equally effective as competitive inhibitors of eIF-4E labeling with [125I]APTM. Like [32P]BPM, [125I]APTM labeled both the full-length (25 kDa) polypeptide and a 16-kDa degradation product, designated eIF-4E*, with labeling occurring in proportion to the amounts of each polypeptide present. A third probe, an azidophenylglycine derivative of m7GTP [( 32P]APGM), the monoanhydride of m7GDP with [32P]-N-(4-azidophenyl)-2-(phosphoramido)acetamide, was also synthesized and shown to label eIF-4E specifically. Unlike [32P]BPM and [125I]APTM, however, [32P]APGM labeled eIF-4E* approximately 4-fold more readily than intact eIF-4E. Tryptic and CNBr cleavage suggested that eIF-4E* consists of a protease-resistant core of eIF-4E that retains the cap-binding site and consists of approximately residues 47-182.

Affinity Labels↗