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PubMed2003

Metabolism of benzyl alcohol via catechol ortho-pathway in methylnaphthalene-degrading Pseudomonas putida CSV86.

Pseudomonas putida CSV86 metabolizes 1- and 2-methylnaphthalene through distinct catabolic and detoxification pathways. In spite of the similarity in the steps involved in the methylnaphthalene detoxification and the toluene side-chain hydroxylation pathways, the strain failed to utilize toluene or xylenes. However, it could grow on benzyl alcohol, 2- and 4-hydroxybenzyl alcohol. Metabolic studies suggest that the benzyl alcohol metabolism proceeds via the benzaldehyde, benzoate, and catechol ortho-cleavage pathway, in contrast to the well established catechol meta-cleavage pathway. Carbon source-dependent enzyme activity studies suggest that the degradation of aromatic alcohol involves two regulons. Aromatic alcohol induces the upper regulon, which codes for aromatic alcohol- and aromatic aldehyde-dehydrogenase and converts alcohol into acid. The aromatic acid so generated induces the specific lower regulon and is metabolized via either the ortho- or the meta-cleavage pathway. CSV86 cells transform 1- and 2-methylnaphthalene to 1- and 2-hydroxymethyl naphthalene, which are further converted to the respective naphthoic acids due to the basal level expression and broad substrate specificity of the upper regulon enzymes.

Alcohol Oxidoreductases↗
PubMed1999

Fixation of spent Saccharomyces cerevisiae biomass for lead sorption.

Spent Saccharomyces cerevisiae cells from a beer fermentation process were evaluated for lead cation sorption. The crude biomass was washed with water and acetone prior to any other treatment. Although the washed biomass showed substantial lead ion sorption it was susceptible to microbial spoilage. Different aldehydes were tested as chemical fixation agents; however, most of them caused drastic lowering of the metal uptake capacity. However, benzaldehyde was not only an excellent fixation agent, but the biomass treated with it also retained its original lead sorption capacity. A mechanism for the fixation process is suggested.

Adsorption↗
PubMed1996

Over-expression of glutathione S-transferases, DT-diaphorase and an apparently tumour-specific cytosolic class-3 aldehyde dehydrogenase by Warthin tumours and mucoepidermoid carcinomas of the human parotid gland.

Cytosolic class-3 aldehyde dehydrogenase (ALDH-3) may help to protect organisms from certain environmental aldehydes by catalysing their detoxification. Consistent with this notion are the reports that relatively high levels of this enzyme are present in tissues, e.g. stomach mucosa and lung, that are so-called ports of entry for such agents. Further, it is found in human saliva. The present investigation revealed that small amounts of this enzyme are also present in human salivary glands; mean values for ALDH-3 activities (NADP-dependent enzyme-catalysed oxidation of benzaldehyde) in cytosolic fractions prepared from submandibular and parotid glands were 52 (range: 29-92) and 44 (range: 13-73) mIU/g tissue, respectively. Essentially identical or slightly lower levels of this enzyme activity were found in pleomorphic adenomas, an undifferentiated carcinoma, and an adenocystic carcinomas, of the parotid gland. On the other hand, Warthin tumours, and mucoepidermoid carcinomas of the parotid gland exhibited relatively elevated levels of ALDH-3 activity; mean values were 1200 (range: 780-1880) and 810 (range: 580-1200) mIU/g tissue, respectively. The ALDH-3 found in normal salivary glands was, as judged by physical, immunological and kinetic criteria, identical to human stomach mucosa ALDH-3 whereas the ALDH-3 present in Warthin tumours, and mucoepidermoid carcinomas, of the parotid gland appeared to be a subtle variant thereof. Qualitatively paralleling the relatively elevated ALDH-3 levels in mucoepidermoid carcinomas and Warthin tumours were relatively elevated levels of glutathione S-transferase (alpha and pi) and DT-diaphorase. As was the case with ALDH-3 levels, glutathione S-transferase (alpha and pi) and DT-diaphorase levels were not elevated in pleomorphic adenomas. Glutathione S-transferase mu was not detected in the two normal parotid gland samples, or in the single pleomorphic adenoma sample, tested. It was found in the single mucoepidermoid carcinoma sample, and in one of the two Warthin tumour samples tested. Cellular levels of ALDH-3, glutathione S-transferases and/or DT-diaphorase could be useful criteria when the decision to be made is whether a salivary gland tumour is a mucoepidermoid carcinoma. ALDH-3 and glutathione S-transferases are known to catalyse the detoxification of two agents that are used to treat salivary gland tumours, viz. cyclophosphamide and cisplatin, respectively. Thus, elevated levels of these enzymes in the mucoepidermoid carcinomas must account for, or at least contribute to, the relative ineffectiveness of these agents when used to treat this tumour.

Adenolymphoma↗
PubMed1980

Studies on the kinetics of cyanohydrin synthesis and cleavage by the the flavoenzyme oxynitrilase.

Almond oxynitrilase (D-alpha-hydroxynitrile lyase, EC 4.1.2.10) catalyzes the reversible condensation of HCN with aldehydes to form D-alpha-hydroxynitriles. Steady-state kinetic parameters for cleavage and synthesis of mandelonitrile and vanillin cyanohydrin were determined at pH 5.5 which is near the pH optimum of the enzyme. Benzaldehyde and vanillin act as competitive inhibitors of cyanohydrin cleavage while noncompetitive inhibition was observed for HCN. The results are consistent with an ordered uni bi mechanism in which aldehyde is the first substrate bound. Competitive inhibition of cyanohydrin cleavage was observed with various carboxylic acids, alcohols and inorganic anions. The effect of structure on the binding of these inhibitors suggests that the active site of oxynitrilase is located near a hydrophobic region and a positively charged group. Inhibitors which are reasonable analogues for cyanide anion, such as azide and thiocyanate, do not bind to the enzyme-aldehyde complex. This suggests that during cyanohydrin formation the species which binds to the enzyme-aldehyde complex is HCN rather than CN-.

Aldehyde-Lyases↗
PubMed1986

Intestinal first pass metabolism of amygdalin in the rat in vitro.

The intestinal first pass metabolism of amygdalin has been investigated in rat small intestine in vitro. The results show that amygdalin is hydrolyzed to prunasin, essentially in the wall of the proximal jejunum. This specific beta(1-6)hydrolytic cleavage of the terminal glucose residue is pH-dependent and can be inhibited by glucono-delta-lactone, a potent inhibitor of the lysosomal beta-glucosidase of the rat intestine. No substrate competition between phloridzin and lactose vs amygdalin was noted. None of the more common soluble beta- or alpha-enzymatic activities of mammalian intestine (alpha-glucosidase, alpha-amylase) or mammalian liver (beta-galactosidase, beta-glucuronidase) were capable of catalyzing the hydrolysis of the terminal glucose from amygdalin at pH's 5.0, 7.0 or 9.0. Furthermore, no metabolic activity of isolated rat livers toward amygdalin and prunasin was observed within two hours of recirculating perfusion. However, cecal contents of conventional rats, exhibited both amygdalin- and prunasin-hydrolyzing activities. The resulting mandelonitrile dissociates spontaneously into cyanide and benzaldehyde. Therefore, our findings indicate that metabolism of amygdalin to prunasin occurring in the proximal part of jejunum is apparently mediated by enzymatic beta(1-6)glucosidase activity of the gut wall. In contrast, the toxicity of amygdalin due to the release of cyanide obviously requires microbiological activities of the gut flora.

Amygdalin↗
PubMed1993

Identification and characterization of a novel class 3 aldehyde dehydrogenase overexpressed in a human breast adenocarcinoma cell line exhibiting oxazaphosphorine-specific acquired resistance.

Associated with the oxazaphosphorine-specific acquired resistance exhibited by a human breast adenocarcinoma subline growing in monolayer culture, viz. MCF-7/OAP, was the overexpression (> 100-fold as compared with the very small amount expressed in the oxazaphosphorine-sensitive parent line) of a class 3 aldehyde dehydrogenase, viz. ALDH-3, judged to be so because it is a polymorphic enzyme (pI values ca. 6.0) present in the cytosol that is heat labile, is insensitive to inhibition by disulfiram (25 microM), much prefers benzaldehyde to acetaldehyde as a substrate and, at concentrations of 4 mM, prefers NADP to NAD as a cofactor. No other aldehyde dehydrogenases were found in these cells. As compared with those of the prototypical class 3 human ALDH-3, viz. constitutive human stomach mucosa ALDH-3, the physical and catalytic properties of the MCF-7/OAP enzyme differed somewhat with regard to pI values, native M(r), subunit M(r), recognition of the subunit by anti-stomach ALDH-3 IgY, pH stability, cofactor influence on catalytic activity, and the ability to catalyze, albeit poorly, the oxidation of an oxazaphosphorine, viz. aldophosphamide. Hence, the MCF-7/OAP ALDH-3 was judged to be a novel class 3 aldehyde dehydrogenase. Small amounts of a seemingly identical enzyme are also present in normal pre- and post-menopausal breast tissue. None could be detected in human liver, kidney or placenta, suggesting that it may be a tissue-specific enzyme.

Adenocarcinoma↗
PubMed1981

Microsomal formation and chemical decomposition of pargyline N-oxide.

Pargyline undergoes metabolic N-oxidation in rat and rabbit liver microsomal preparations. The reaction requires oxygen and is NADPH dependent. N-oxidation and N-demethylation are equal in both control and induced rat liver microsomes, while N-oxidation is more dominant in rabbit tissue. Experiments investigating the CO-sensitivity and the effects of metyrapone suggest that cytochrome P-450 systems are involved in both reactions in the rat while an additional enzyme is responsible for the N-oxidation in the rabbit. Pargyline N-oxide is characterized by chemical instability and undergoes two consecutive rearrangements to yield propenal and Schiff bases, the latter undergoing hydrolysis to aldehydes and primary amines. Accordingly, due to the inherent instability of the N-oxide, metabolic N-oxidation of pargyline is, in addition to alpha-carbon oxidation, indicated as a metabolic route to benzaldehyde. Similarly the ease with which pargyline N-oxide generates propenal implicates N-oxidation as a metabolic route to be considered when evaluating the toxicity of pargyline.

Animals↗
PubMed1991

Effects of some aldehydes on brain microtubular protein.

4-Hydroxynonenal is one of the main breakdown products of lipid peroxidation. It has an antiproliferative effect, which may partly be the consequence of an interaction with cytoskeletal structures. Its effects on microtubular protein are compared with those of homologous aldehydes with the same number of carbon atoms, and with that of benzaldehyde. Unlike the other aliphatic aldehydes, this latter aldehyde does not impair microtubular functions at every concentration in the range. Nonanal has the greatest effect on tubulin polymerization, whereas it only slightly impairs colchicine binding activity. 2-Nonenal and 4-hydroxynonenal have less inhibiting effect on tubulin polymerization; their effect on colchicine binding activity is dose-dependent. The targets of 4-hydroxynonenal on tubulin are -SH groups; the action mechanism of other aldehydes has not yet been identified.

Aldehydes↗
PubMed1991

Effect of various chemicals on the aldehyde dehydrogenase activity of the rat liver cytosol.

The cytosolic activity of aldehyde dehydrogenase (ALDH) was studied in the rat liver, after acute administration of various carcinogenic and chemically related compounds. Male Wistar rats were treated with 27 different chemicals, including polycyclic aromatic hydrocarbons, aromatic amines, nitrosamines, azo dyes, as well as with some known direct-acting carcinogens. The cytosolic ALDH activity of the liver was determined either with propionaldehyde and NAD (P/NAD), or with benzaldehyde and NADP (B/NADP). The activity of ALDH remained unaffected after treatment with 1-naphthylamine, nitrosamines and also with the direct-acting chemical carcinogens tested. On the contrary, polycyclic aromatic hydrocarbons, polychlorinated biphenyls (Arochlor 1254) and 2-naphthylamine produced a remarkable increase of ALDH. In general, the response to the effectors was disproportionate between the two types of enzyme activity, being much in favour for the B/NADP activity. This fact resulted to an inversion of the ratio B/NADP vs. P/NAD, which under constitutive conditions is lower than 1. In this respect, the most potent compounds were found to be polychlorinated biphenyls, 3-methylcholanthrene, benzo(a)pyrene and 1,2,5,6-dibenzoanthracene. Our results suggest that the B/NADP activity of the soluble ALDH is greatly induced after treatment with compounds possessing aromatic ring(s) in their molecule. It is not known, if this response of the hepatocytes is related with the process of chemical carcinogenesis.

Aldehyde Dehydrogenase↗
PubMed1992

Effects of steroids on the olfactory function of the dog.

Twenty-four (24) mature, mixed breed, healthy dogs weighing from 14.6 kg to 27.6 kg were used to study the effects of various steroids on the olfactory function of the dog using olfactory detection threshold as an index. Two odorants were used, viz; benzaldehyde and eugenol. Of the various steroids used, only dexamethasone produced classical signs of Cushing's syndrome in the dogs. However, all dogs that received either dexamethasone alone or hydrocortisone plus DOCA exhibited a significant elevation in the olfactory detection threshold for both odorants without any observable structural alteration of the olfactory tissue using light microscopy. On the other hand, neither DOCA, hydrocortisone alone, nor any of the vehicles used in the study significantly altered the olfactory function of the dogs. The results show that Cushing's syndrome can be experimentally produced in dogs using exogenous steroids and that this condition diminishes the olfactory capability of the dog without producing classical signs of the disease.

Adrenal Cortex Function Tests↗
PubMed1985

Peroxybenzoylnitrate: measurements in smog chambers and in urban air.

Peroxybenzoylnitrate (PBzN, C6H5C(O)OONO2), a photochemical atmospheric pollutant and powerful eye irritant, was detected at greater than or equal to 10 ng following aqueous alkaline hydrolysis to benzoate ion and analysis by ion chromatography with ultraviolet detection. Method validation studies and studies of potential interferents including benzaldehyde and benzoic acid are described, together with applications to PBzN measurements in environmental chamber atmospheres and in ambient air.

Air Pollutants↗
PubMed1992

Oxygen transfer reactions by synthetic analogues of iron-bleomycin.

Synthetic analogues of the iron-bleomycins, namely [Fe(PMA)]2+ and [Fe(PMA)]+, have been studied as oxotransfer agents. Oxygen transfer has been observed using iodosobenzene (PhIO), hydrogen peroxide, and dioxygen as oxygen sources. The primary substrates were cis- and trans-stilbene. The products were determined to be cis- and trans-stilbene oxide, benzaldehyde, and deoxybenzoin. These products were recovered in ratios similar to those reported for the iron-bleomycins, albeit in lower yields. Iron complexes of simpler analogues are inactive as oxotransfer agents. This study provides further support that PMAH is an accurate model of the metal binding region of bleomycin.

Benzaldehydes↗
PubMed1985

Colorimetric assay of gramicidin A in the presence of surfactants and phospholipids.

Gramicidin A, a hydrophobic polypeptide containing 4 tryptophan residues/molecule, may be determined quantitatively after reaction with 4-(dimethylamino)benzaldehyde, a method previously proposed for tryptophan analysis. The assay may be carried out even in the presence of various surfactants and phospholipids at high concentrations.

Benzaldehydes↗
PubMed1988

In vitro studies of the biological effects of cigarette smoke condensate. III. Induction of SCE by some phenolic and related constituents derived from cigarette smoke. A study of structure-activity relationships.

Since our earlier studies of 23 individual weakly acidic constituents of cigarette smoke indicated that benzenes having vicinal oxygenation or a conjugated double bond induce sister-chromatid exchanges (SCE), we have now selected and examined a complementary set of 27 smoke constituents for their SCE-inducing properties. Of the 50 compounds tested in all, 23 were found to induce SCE, and these include all benzaldehydes but one and the majority of the compounds having a conjugated carbon-carbon double bond as well as several of the guaiacols. These groups of active compounds comprise important flavourants such as vanillin, ethylvanillin, isoeugenol and guaiacol. The structure-activity relationships encountered here may be useful in predicting the SCE-inducing activity of related compounds.

Benzaldehydes↗
PubMed1992

BW12C-induced changes in haemoglobin-oxygen affinity in mice and its influence on the radiation response of a C3H mouse mammary carcinoma.

The effect of the substituted benzaldehyde BW12C on haemoglobin-oxygen binding affinity, tumour radiation response and blood perfusion were investigated in a C3H mouse mammary carcinoma grown in the feet of CDF1 mice. Mouse P50 (partial pressure of oxygen at half saturation) was estimated using an ABL blood gas analyzer; radiation response determined from tumour regrowth and local tumour control assays; and tumour blood perfusion measured with a 86RbCl extraction procedure. A single intravenous injection of BW12C substantially decreased mouse P50. This effect was dependent on the time after injection with the nadir observed within 15 min and only returning to normal after several hours. It was also dependent on drug dose, the decrease becoming larger with increasing concentration, reaching a maximum 50% reduction at 70 mg/kg. The decrease in P50 could be maintained for at least 6 h following injection of 70 mg/kg, if mice were also given 25 mg/kg at hourly intervals. However, no changes in radiation response or tumour blood perfusion were observed with either single or multiple administrations of BW12C. These results suggest that BW12C induced changes in tumour hypoxia reported by several groups of workers, may not be entirely the result of a change in haemoglobin-oxygen affinity.

Animals↗
PubMed1991

Urinary excretion of S-benzylmercapturic acid as an indicator of N-nitroso-N-methylbenzylamine exposure.

The excretion of S-benzylmercapturic acid (SBzMA) in the urine of rats treated with N-nitroso-N-methylbenzylamine (NMBzA) was determined by gas chromatography-mass spectrometry (GC-MS). The identity of SBzMA in the urine was confirmed by full scan GC-MS. The amount of urinary SBzMA varied with the dose of NMBzA (up to 5 mg/kg) and with rat strain. For the three strains investigated, most of a 2.5 mg/kg dose of SBzMA was excreted within 24 h. Comparison of the levels of this SBzMA excreted by rats treated with equivalent doses of either NMBzA or benzaldehyde indicates that urinary SBzMA is derived mainly from benzylating species resulting from the hydroxylation of the methyl group of NMBzA.

Acetylcysteine↗
PubMed1982

Cytostatic and reverse-transforming therapies of cancer - a brief review and future prospects.

Cytostatic cancer therapies are defined as those which retard cancer growth by intervening selectively in the disordered control mechanisms responsible for malignant behavior, without producing direct cytotoxicity. A number of possible approaches to cytostatic therapy are now under investigation and are briefly reviewed here - cyclic AMP congeners and promoters, prostaglandin precursors, thioproline, benzaldehyde, retinoids, interferon, chalones, antineoplastons, protease inhibitors, polar solvents. Suggestions for the further development of cytostatic therapies are offered, and a role for cytostatic therapy within a broad global concept of cancer therapy is proposed.

Animals↗
PubMed1995

Determination of semicarbazide-sensitive amine oxidase activity in human plasma by high-performance liquid chromatography with fluorimetric detection.

We report here a simple and sensitive method for the measurement of semicarbazide-sensitive amine oxidase (SSAO) activity in human plasma. Benzaldehyde, generated during a 1-h incubation of plasma with benzylamine, is derivatized with the specific aldehyde reagent dimedone after prior deproteinization. Quantitation of the derivatization product is done by automated injection onto an isocratic high-performance liquid chromatographic system with fluorimetric detection. The assay shows good linearity and reproducibility (intra-assay C.V. 7%). Detection limit is 25 mU/l (= pmol/ml/min). In 51 healthy controls (age 49 +/- 13 yr, 20 males) the measured SSAO activity was 352 +/- 102 mU/l (mean +/- S.D.). A large number of samples (70-80) can easily be processed in one day by one technician.

Adult↗