Disease relevance of guaiacol

• Endogenous peroxidase activity, measured in vitro by guaiacol oxidation, occurred in substantially higher amounts in the primary ovarian adenocarcinomas than in benign tumors and control ovaries and could be demonstrated within ovarian adenocarcinoma cells by electron microscopy [1].
• When eosinophil peroxidase (EPO) was incubated with Staphylococcus aureus (staph) approximately 40% remained firmly bound to the bacteria as indicated by guaiacol assay [2].
• Guaiacol -- a new compound in the treatment of gastro-oesophageal reflux [3]?
• The presented work focuses on the characterization of the role of hydrogen peroxide (H2O2)-producing (NADH peroxidase) and H2O2-consuming peroxidase (guaiacol POD) in the apoplastic washing fluid (AWF) of leaves for early stages of Mn toxicity and genotypic differences in Mn tolerance of cowpea [4].
• The mean TPO activity measured by guaiacol as well as triiodide assays was significantly increased in multinodular goiter, whereas a nonsignificant increment was observed in cold adenoma [5].

High impact information on guaiacol

• In contrast to APX, the guaiacol-utilizing peroxidases, which participate in the synthesis and crosslinking of cell wall components as part of the defense response, are not inhibited by SA or INA [6].
• The guaiacol assay failed to show a definite pattern of inheritance in two families with MPO-deficient subjects [7].
• The resulting tritiated product, guaiacol, is readily extracted into toluene and quantified by scintillation counting [8].
• After i.p. administration, CLO was eliminated unchanged in feces and as two components which were chromatographically identical to synthetic CLO analogues bearing a m-methoxy-p-hydroxyphenyl (guaiacol) moiety in place of one or the other of its phenyl rings [9].
• The inactivation of the enzyme in the presence of SCN- and H2O2 is prevented by electron donors such as iodide or guaiacol [10].

Chemical compound and disease context of guaiacol

• Methyl-substituted phenolics such as 4-methylcatechol (MCAT) and methylhydroquinone (MHQ) produced, in addition to oxidative toxicity, marked cytotoxic effects against OxyR(+) cells, thus revealing a mechanism of toxicity not mediated by hydrogen peroxide that could involve quinones and quinone methides arising from MCAT and MHQ oxidation [11].
• In OxyR(+) cells, where the oxidative toxicity is inhibited, DEA/NO promoted exceptional increases in the cytotoxicity of CAT and 3,4-dihydroxycinnamic (caffeic) acid (CAF), which both exhibited very low oxidative cytotoxicity, as well as in that of MCAT, HQ, and MHQ [11].
• Several strains of Bacillus megaterium and a strain of Streptomyces are shown to convert vanillate to guaiacol (o-methoxyphenol) and CO2 by nonoxidative decarboxylation [12].
• Two alternative forms of protocatechuate 3,4-dioxygenase (PCase) have been purified from Moraxella sp. strain GU2, a bacterium that is able to grow on guaiacol or various other phenolic compounds as the sole source of carbon and energy [13].
• The peroxidase activity in adenoma was almost similar in the guaiacol oxidation assay and approximately one half in the iodide oxidation assay as compared with that in diffuse goiter [14].

Biological context of guaiacol

• Family studies on myeloperoxidase (MPO) deficiency have been carried out by quantitating the peroxidase activity of granulocyte preparations with three methods, namely guaiacol peroxidation, alanine decarboxylation, and spectroscopic analysis [7].
• Noncompetitive kinetics are observed for the inhibition of guaiacol and iodide oxidation by thioanisole and of guaiacol oxidation by iodide [15].
• Distribution of guaiacol peroxidase in human endometrium and endocervical epithelium during the menstrual cycle [16].
• Cytochrome c peroxidase (CCP) from Saccharomyces cerevisiae was subjected to directed molecular evolution to generate mutants with increased activity against the classical peroxidase substrate guaiacol, thus changing the substrate specificity of CCP from the protein cytochrome c to a small organic molecule [17].
• Intermittent oral administration of 2M4MP and 2M4EP, but not 2MP, significantly prevented reductions of bone mineral density in total femur, distal femur and tibia, in addition to alterations of several osteoclastic parameters on histomorphometric analysis, when determined 28 days after ovariectomy in mice [18].

Anatomical context of guaiacol

• TPO was prepared from Graves' thyroid glands, solubilized by n-octyl glucoside, and its activity was assayed by the guaiacol method [19].
• Properties of guaiacol peroxidase activities isolated from corn root plasma membranes [20].
• The present study was first aimed at a complete steady-state kinetic analysis of the reaction between guaiacol (2-methoxyphenol) and the myeloperoxidase (MPO)/H2O2 system, including a description of the isolation and purification of MPO from human polymorphonuclear neutrophil cells [21].
• A localization of guaiacol peroxidase in rough-endoplasmic-reticulum membranes (or in membranes related to them) seems very likely [22].
• 1. An enzyme that can be induced in rat uteri by oestrogens and that catalyses the oxidation of guaiacol and the metabolism and binding of [4-14C]oestradiol to protein in the presence of H2O2 was partially purified by (NH4)2SO4 fractionation and polyacrylamide-gel chromatography [23].

Associations of guaiacol with other chemical compounds

• Proton-carbon correlation NMR spectroscopy was used to demonstrate the specific incorporation of deuterium from D2O into guaiacol obtained from vanillic acid [24].
• Resting cells of Rhodotorula rubra converted transferulic acid (1) to vanillic acid (2), then to guaiacol (3) and protocatechuic acid (4), under aerobic conditions [24].
• Horseradish peroxidase, when incubated with diethyl pyrocarbonate (DEPC), a histidine-specific reagent, shows time-dependent inactivation to oxidize aromatic electron donor, guaiacol [25].
• Mechanisms of ferulic acid conversions to vanillic acid and guaiacol by Rhodotorula rubra [24].
• In addition, the purified enzyme had a peroxidase activity with guaiacol and potassium iodide as hydrogen donors, but not a catalase activity [26].

Gene context of guaiacol

• Indeed, the MCG/EPO complex had significantly greater iodinating and bactericidal activity than the free enzyme when standardized to equal guaiacol units of peroxidase activity [27].
• The SCN- normally present in human saliva will reduce observed reaction rates by simple competition kinetics in the ABTS, guaiacol and pyrogallol assays and will increase the rates observed when Cl- is used as a donor in NBS assay for MPO [28].
• 2. TPO enzyme activity (guaiacol assay) of unlabelled TPO was decreased after treatment with EndoH but not with other glycosidases [29].
• The holoprotein was purified to homogeneity, which displayed a blue color typical of laccases and oxidized canonical laccase substrates such as guaiacol and 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonate) [30].
• The catechol-O-methyltransferase (COMT) activity was measured in cytosolic and membrane fractions at 37 degrees C, giving values of 33 and 114 units/mg of protein, respectively (1 unit produces 1 nmol of guaiacol/h) [31].

Analytical, diagnostic and therapeutic context of guaiacol

• The peroxidase activity as followed with guaiacol and hydrogen peroxide and the tryptophan-stimulated conversion of prostaglandin G1 to H1 were not dissociable as examined by isoelectric focusing, heat treatment, pH profile, and heme specificity [32].
• After three rounds of DNA shuffling and screening, mutants were isolated which possessed a 300-fold increased activity against guaiacol and an up to 1000-fold increased specificity for this substrate relative to that for the natural substrate [17].
• Guaiacol was detected by thin-layer chromatography [12].
• Based on the identification of the reaction product by electrospray ionization-mass spectrometry, a model compound of beta-aryl ether, alpha-(2-methoxyphenoxy)-beta-hydroxypropiovanillone (MPHPV), was transformed by LigF or LigE to guaiacol and alpha-glutathionyl-beta-hydroxypropiovanillone (GS-HPV) [33].
• Pyrolysis/gas chromatography/mass spectrometry results showed a decrease of polyphenols pyrolysis products, mainly phenol and guaiacol, with the incubation time [34].

References