Microbial oxidation of methanol: Properties of crystallized alcohol oxidase from a yeast, Pichia sp

Alcohol oxidase (alcohol:oxygen oxidoreductase) was crystallized from a methanolgrown yeast, Pichia sp. The crystalline enzyme is homogenous as judged from polyacrylamide gel electrophoresis. Alcohol oxidase catalyzed the oxidation of short-chain primary alcohols (C₁ to C₆), substituted primary alcohols (2-chloroethanol, 3-chloro-1-propanol, 4-chlorobutanol, isobutanol), and formaldehyde. The general reaction with an oxidizable substrate is as follows: Primary alcohol + O₂ → aldehyde + H₂O₂ Formaldehyde + O₂ → formate + H₂O₂. Secondary alcohols, tertiary alcohols, cyclic alcohols, aromatic alcohols, and aldehydes (except formaldehyde) were not oxidized. The K_m values for methanol and formaldehyde are 0.5 and 3.5 mm, respectively. The stoichiometry of substrate oxidized (alcohol or formaldehyde), oxygen consumed, and product formed (aldehyde or formate) is 1:1:1. The purified enzyme has a molecular weight of 300,000 as determined by gel filtration and a subunit size of 76,000 as determined by sodium dodecyl sulfate-gel electrophoresis, indicating that alcohol oxidase consists of four identical subunits. The purified alcohol oxidase has absorption maxima at 460 and 380 nm which were bleached by the addition of methanol. The prosthetic group of the enzyme was identified as a flavin adenine dinucleotide. Alcohol oxidase activity was inhibited by sulfhydryl reagents (p-chloromercuribenzoate, mercuric chloride, 5,5′-dithiobis-2-nitrobenzoate, iodoacetate) indicating the involvement of sulfhydryl groups(s) in the oxidation of alcohols by alcohol oxidase. Hydrogen peroxide (product of the reaction), 2-aminoethanol (substrate analogue), and cupric sulfate also inhibited alcohol oxidase activity.     

Acyl-CoA oxidase from Candida tropicalis

The preparation of a highly purified acyl-CoA oxidase from the cell extract of an n-alkane-utilizing yeast, Candida tropicalis, is described. It can be crystallized from ammonium sulfate solutions without an increase in specific activity, and is homogeneous on ultracentrifuge and disc electrophoresis. The enzyme is an octamer with approximately a 600,000 molecular weight, and has an isoelectric point of 5.5. It exhibits a typical flavoprotein spectrum with absorption maxima at 277, 365 and 445 nm, and contains 8 mol of FAD per mol of enzyme. The enzyme catalyzes the stoichiometric conversion of palmitoyl-CoA and O₂ into 2-hexadecenoyl-CoA and H₂O₂. It oxidizes acyl-CoAs with carbon chain lengths of 4 to 20, and is most active toward lauroyl-CoA, but acetyl- and succinyl-CoAs are not oxidized. The enzyme is sulfhydryl dependent and is inactivated by silver and mercury compounds.     

Purification and characterisation of monoamine oxidase from Avena sativa

FAD-containing monoamine oxidase (MAO; EC 1.4.3.4) oxidises monoamines to their corresponding aldehydes, H₂O₂, and NH₃. It has been purified to homogeneity in mammals, but to our knowledge, there have been no reports of the enzyme in plants. MAO activity was detected in Avena sativa seedlings during germination using benzylamine as substrate. The enzyme was purified to homogeneity (as assessed by native PAGE) by Sephadex G-25, DEAE Sephacel, hydroxyapatite, Mono Q, and TSK-GEL column chromatographies. The molecular mass estimated by gel filtration using the TSK-GEL column was 220?kDa. SDS-PAGE yielded four distinct protein bands of 78, 58, 55, and 32?kDa molecular masses. The pI value of the enzyme was 6.3. The enzyme showed high substrate specificity for an endogenous amine, phenethylamine, which was oxidised to phenylacetaldehde, but not for ethylamine, propylamine, butylamine, pentylamine, dopamine, serotonin, tryptamine, or tyramine. The K _m values for benzylamine and phenethylamine were 2.7?×?10^?4 and 7.1?×?10^?4?M, respectively. Enzyme activity was not inhibited by pargyline, clorgyline, semicarbazide, or Na-diethyldithiocarbamate. Benzaldehyde, the product of benzylamine oxidation, exhibited strong competitive inhibition of enzyme activity with a Ki of 3???M. FAD was identified by ODS-column chromatography as an enzyme cofactor. The enzyme contained 2?mol of FAD per 220,000?g of enzyme.     

Polyamine oxidase from water hyacinth: purification and properties

Polyamine oxidase was purified to homogeneity from leaves of water hyacinth by the criterion of sodium dodecyl sulfate gel electrophoresis (SDS disc PAGE). The enzyme showed a high specificity for spermidine and spermine (K_m values 28 micromolar and 20 micromolar, respectively). The optimal pH of the enzyme for both spermidine and spermine was 6.5. The molecular weight of the enzyme estimated by Sephadex G-200 gel filtration was 87,000, while SDS disc PAGE gave a single band at the molecular weight of 60,000. Octamethylenediamine and quinacrine were strong inhibitors of the enzyme, but p-chloromercuribenzoate was without effect. A prosthetic group in the enzyme was identified as flavin adenine dinucleotide.     

Characterization of cytochrome oxidase purified from rat liver

The purpose of this study was to characterize the physical properties of cytochromec oxidase from rat liver. The enzyme was extracted from isolated mitochondria with nonionic detergents and further purified by ion-exchange chromatography on DEAE Bio-Gel A. The purified enzyme contained 9.64 nmol heme a/mg protein and one iron atom plus one copper atom for each heme a. The specific activity of the final preparation was 146 µmol of ferrocytochromec oxidized/min · mg protein, measured at pH 5.7. The spectral properties of the enzyme were characteristic of purified cytochrome oxidase and indicated that the preparation was free of cytochromesb, c, andc ₁. In analytical ultracentrifugation studies, the enzyme sedimented as a single component with anS ^20,w of5.35S. The Stokes radius of the enzyme was determined by gel filtration chromatography and was equal to 75 Å. The molecular weight of the oxidase calculated from its sedimentation coefficient and Stokes' radius was 180,000, indicating that the active enzyme contained two heme a groups. The purified cytochrome oxidase was also subjected to dodecyl sulfate-polyacrylamide gel electrophoresis in order to determine its components. The enzyme was resolved into five polypeptides with the molecular weights of I, 27,100; II, 15,000; III, 11,900; IV 9800; and V, 9000.     

Administration of isolated chicken L-gulonolactone oxidase to guinea pigs evokes ascorbic acid synthetic capacity

l-Gulonolactone oxidase was purified from chicken kidney microsomes in order to test whether this enzyme had potential advantages in our enzyme therapy studies. Chicken was selected because it has an enzyme that is structurally distinct from the enzyme in mammals and has high enzyme activity. An essentially homogeneous preparation of chicken l-gulonolactone oxidase is obtained by a seven-step procedure. Certain characteristics of this enzyme are presented. The enzyme was found to be quite unstable. However, immunoprecipitates of the enzyme are greatly stabilized. Therefore, this form was administered to young ascorbic acid-deficient guinea pigs that had been supplemented with l-gulonolactone. These animals showed a marked increase in plasma ascorbic acid concentrations.     

Molecular and Enzymatic Properties of Pyridoxamine (Pyridoxine) 5′-Phosphate Oxidase from Baker’s Yeast

Pyridoxamine (pyridoxine) 5′-phosphate oxidase purified from baker’s yeast was found to have a molecular weight of ca, 55,000 daltons based on polyacrylamide gel electrophoresis. The size of the enzyme subunit was analyzed by gel electrophoresis in the presence of sodium dodecylsulfate. This showed that the enzyme was composed of two nonidentical subunits with a molecular weight of 27,000 and 25,000 daltons. Fluorescence titration of the apoenzyme with FMN suggested that the holoenzyme contained one mol of FMN per mol of the enzyme. The K_m value of FMN for apoenzyme was calculated to be ca. 16 nm on both activities of pyridoxamine 5′-phosphate oxidase and pyridoxine 5′-phosphate oxidase.     

Purification and some properties of polyphenol oxidase from root-forming carrot callus tissues

1. Polyphenol oxidase (o-diphenol : O₂ oxidoreductase; E.C.1.10.3.1 [EC] ) was isolated from the other phenolases which werepresent in root-forming carrot callus, and its properties wereexamined. 2. The enzyme was purified about 45-fold over crudeextracts (precipitates between 40–70% saturation widiammonium sulfate) by a combination of Bio-gel filtration, protein-bagfiltration, and carboxymethyl cellulose chromatography. Thepurified oxidase was homogeneous according to polyacrylamidegel electrophoresis and Sephadex gel filtration. It was confirmedby CM-cellulose chromatography that the enzyme was absent incallus tissues without accompanying redifferentiation. 3. Themolecular weight of this oxidase was estimated to be 110,000-120,000 from molecular weight-mobility profiles on polyacrylamidegels containing sodium dodecyl sulfate and molecular size-elutionvolume correlations on Sephadex G-150 columns. 4. The enzymeoxidized o-diphenols but showed no detectable activity againstmonophenols. Pyrocatechol, dopamine, caffeic acid, and chlorogenicacid were effectual substrates of the enzyme with K_m valuesranging from 10^–3 M to 10^–5M. The enzyme effectivelycatalyzed the oxidation of o-diphenols over the range of pH6.0 to 7.0 and was readily inactivated by heating. The enzymeactivity was slightly influenced by increasing ionic strength.The initial rate of the enzymic reaction was enhanced by additionof Cu²⁺, Co²⁺ and Mn²⁺ ions, and was reduced in the presenceof DTT, PCMPS, glycylglycine, and DIECA. (Received June 17, 1978; )     

The molecular properties of the copper enzyme galactose oxidase

Galactose oxidase (EC 1.1.3.9) has been purified 140-fold by DEAE- and CM-cellulose chromatography from cultures of Polyporus circinatus. The enzyme has a molecular weight of 68,000 ± 3,000 as determined by sedimentation equilibrium, sodium dodecyl sulfate-acrylamide gel electrophoresis, Sephadex G-150 chromatography, and osmometry. Galactose oxidase is a single-chain protein which does not self-associate. Charge isozymes of the enzyme are detected by ion-exchange chromatography and gel electrophoresis. The amino acid composition determined herein is significantly different from that previously reported (Kelly-Falcoz, F., Greenberg, H., And Horecker, B. L. (1965) J. Biol. Chem.240, 2966–2970). The enzyme contains 1% by weight of neutral carbohydrate.Galactose oxidase contains 1 g-atom of copper per 70,000 g of protein. The metal does not contribute to the electrophoretic or isozymic properties of the protein. However, the sedimentation coefficients of the holo- and apoenzymes, 4.76S and 4.83S, respectively, do suggest that small differences in protein conformation accompany the removal of the copper from the holoenzyme.Attempted sulfhydryl group titration of galactose oxidase shows that the holoenzyme is resistant to denaturation. However, in β-mercaptoethanol-guanidine HCl 5 half-cystine residues are titrated in the apoenzyme. On a dry-weight basis, the E_1cm^1% value for galactose oxidase at 280 nm is 15.4. Galactose oxidase has an isoelectric point above pH 10 which is a probable source of some of its anomalous behavior in physical measurements and enzyme-activity determinations.     

Bacterial short-chain acyl-CoA oxidase: production,purification and characterization

An Arthrobacter nicotianae strain has been found to produce an inducible acyl coenzyme A (CoA) oxidase. Nine times more butyryl-CoA oxidase activity, compared to palmitoyl-CoA oxidase, was found in the cell extract. The addition of flavin adenine dinucleotide (FAD) caused an increase in acyl-CoA oxidase activity and thermal stability. The purified enzyme exhibited a relative molecular mass of 50 000 on sodium dodecyl sulphate-polyacrylamide gel electrophoresis and 100 000 under non-denaturing conditions. Acyl-CoA oxidase from Arthrobacter nicotianae is highly specific towards short-chain fatty acids. The fastest O₂ uptake was observed with butyryl-CoA as substrate. The enzyme is inhibited by silver and mercury salts.To Professor Dr. Helmut Simon for his 65th birthday Correspondence to: H. Sztajer     

Purification and Properties of Cyclodextrin Glucanotransferase from Brevibacterium sp. No. 9605

Cyclodextrin glucanotransferase (EC 2.4.1.19) from Brevibacterium sp. No. 9605 was purified to homogeneity by chromatography on butyl-Toyopearl 650M, γ-cyclodextrin-Sepharose 4B, and Toyopearl HW-55S. The molecular weight of the purified enzyme was estimated to be 75,000 by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The isoelectric point of the purified enzyme was 2.8. The optimum pH and temperature were pH 10 and 45°C, respectively. The enzyme was stable at the range of pH 6–8 and at temperatures 50°C or less in the presence of CaCl₂. The enzyme produced mainly γ-cyclodextrin from starch in the initial stage of reaction, but later, the proportion of β-cyclodextrin was increased.     

Purification and Properties of Dimethylglycine Oxidase from Cylindrocarpon didymum M–1

Dimethylglycine oxidase was purified to homogeneity from the cell extract of Cylindrocarpon didymum M–1, aerobically grown in medium containing betaine as the carbon source. The molecular weight of the enzyme was estimated to be 170,000 by the gel filtration method and 180,000 by the sedimentation velocity method. The enzyme exhibited an absorption spectrum characteristic of a flavoprotein with absorption maxima at 277, 345 and 450 nm. The enzyme consisted of two identical subunits with a molecular weight of 82,000, and contained two mol of FAD per mol of enzyme. The flavin was shown to be covalently bound to the protein. The enzyme was inactivated by Ag⁺, Hg²⁺, Zn²⁺ and iodoacetate. The enzyme oxidized dimethylglycine but was inert toward choline, betaine, sarcosine and alkylamines. Km and Vmax values for dimethylglycine were 9.1 mm and 1.22 μmol/min/mg, respectively. The enzyme catalyzed the following reaction: Dimethylglycine+O₂+H₂O → sarcosine+formaldehyde+H₂O₂.     

A simple purification procedure of D-amino-acid oxidase from <Emphasis Type="Italic">Candida guilliermondii</Emphasis>

D-amino-acid oxidase (EC 1.4.3.3) was purified about 1480-fold from the yeast Candida guilliermondii using chromatofocusing method. The purification procedure gave an enzyme preparation which is greater than 90% homogenous on SDS-polyacrylamide gels with a specific activity of 11.54 U/mg at 30°C with D-proline as substrate with the yield of total activity 9.3%. The molecular weights of subunit and native enzyme were determined to be 38.4 and 78.6 kDa by SDS-polyacrylamide gel electrophoresis and gel-filtration, respectively, suggesting that the native enzyme exists as a homodimer. A single molecular form with an isoelectric point of 6.85 was detected in analytical isoelectrofocusing. The optimum pH and temperature were 8.0 and 33°C. An enzyme shows stability in the pH range from 7.4 to 9.0 and at the temperature no higher than 38°C. Activation energy for D-amino-acid oxidase reaction was calculated to be 60 kJ/mol at 30°C. The strict D-isomer specificity of the enzyme is confirmed, since no reaction could be detected with L-amino acids, and a large number of D-amino acids could be substrates for this enzyme. K _m and V _max values were determined for D-proline and D-alanine, which, among 22 tested, were the best substrates of the enzyme. D-amino-acid oxidase from the yeast C. guilliermondii is a flavoprotein oxidase in which the prosthetic group is tightly, but not covalently, bound FAD. The enzyme is completely inhibited by sodium benzoate, SH-oxidizing agents, but not by sodium azide, toluene or chloroform.     

Optimization of culture conditions and properties of immobilized sulfide oxidase from Arthrobacter species

Arthrobacter species strain FR-3, isolated from sediments of a swamp, produced a novel serine-type sulfide oxidase. The production of sulfide oxidase was maximal at pH 7.5 and 30 degrees C. Among various carbon and nitrogen sources tested, glucose and yeast extract were found to be the most effective substrates for the secretion of sulfide oxidase. The sulfide oxidase was purified to homogeneity and the molecular weight of the purified enzyme was 43 kDa when estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The purified sulfide oxidase can be effectively immobilized in DEAE (diethylaminoethyl)-cellulose matrix with a yield of 66%. The purified free and immobilized enzyme had optimum activity at pH 7.5 and 6.0, respectively. Immobilization increases the stability of the enzyme with respect to temperature. The half-life of the immobilized enzyme was 30 min at 45 degrees C, longer than that of the free enzyme (10 min). The purified free sulfide oxidase activity was completely inhibited by 1 mM Co2+ and Zn2+ and sulfhydryl group reagents (para-chloromercuribenzoic acid and iodoacetic acid). Catalytic activity was not affected by 1 mM Ca2+, Mg2+, Na+ and metal-chelating agent (EDTA).     

PURIFICATION AND CHARACTERIZATION OF GLYCOLATE OXIDASE FROM THE BROWN ALGA SPATOGLOSSUM PACIFICISM (PHAEOPHYTA)1

Glycolate oxidase was purified to apparent homogeneity from the brown alga Spatoglossum pacificum Yendo. The 1326-fold purified glycolate oxidase enzyme exhibited a specific activity of 22. 4 micromoles glyoxylate formed ·min^?1·mg protein^?1. The molecular weight of the native enzyme was estimated to be 230,000 by gel filtration. The subunit molecular weight of the enzyme was determined to be 49,000 by sodium dodecyl sulfate–polyacrylamide gel electrophoresis, suggesting that the native enzyme is a tetramer. There were two absorption peaks at 345 and 445 nm, indicating that glycolate oxidase is a flavoprotein. This enzyme had a high isoelectric point (pI 9.6) and a high pH optimum (pH 8.3). The K_m values for glycolate and l -lactate were 0.49 and 5.5 mM, respectively. This enzyme also had a broad specificity for other straight-chain α-hydroxy acids but not for β-hydroxyacids. Cyanide, azide, N-ethylmaleimide, and p-chloromercuribenzoic acid did not affect the enzyme, whereas 2-pyridylhydroxymethanesulfonic acid strongly inhibited it. These properties of glycolate oxidase from the brown alga S. pacificum are similar to the properties of the glycolate oxidasesfrom higher plants. Polyclonal antibodies raised against the polypeptide fragment of Spatoglossum glycolate oxidase could recognize glycolate oxidase from Spinacia oleracea L., although the cross-reactivity was weak. The N-terminal sequence of two internal polypeptide fragments of the enzyme from S. pacificum showed a high degree of similarity to that of glycolate oxidase from higher plants. These results suggest that glycolate oxidase from higher plants and brown algae share the same ancestral protein.     

Purification and characterization of an NADH oxidase from extremely thermophilic anaerobic bacterium Thermotoga hypogea

Thermotoga hypogea is an extremely thermophilic anaerobic bacterium capable of growing at 90°C. It was found to be able to grow in the presence of micromolar molecular oxygen (O₂). Activity of NADH oxidase was detected in the cell-free extract of T. hypogea, from which an NADH oxidase was purified to homogeneity. The purified enzyme was a homodimeric flavoprotein with a subunit of 50 kDa, revealed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. It catalyzed the reduction of O₂ to hydrogen peroxide (H₂O₂), specifically using NADH as electron donor. Its catalytic properties showed that the NADH oxidase had an apparent V_max value of 37 mol NADH oxidized min^–1 mg^–1 protein. Apparent K_m values for NADH and O₂ were determined to be 7.5 M and 85 M, respectively. The enzyme exhibited a pH optimum of 7.0 and temperature optimum above 85°C. The NADH-dependent peroxidase activity was also present in the cell-free extract, which could reduce H₂O₂ produced by the NADH oxidase to H₂O. It seems possible that O₂ can be reduced to H₂O by the oxidase and peroxidase, but further investigation is required to conclude firmly if the purified NADH oxidase is part of an enzyme system that protects anaerobic T. hypogea from accidental exposure to O₂.     

Purification and Properties of Sarcosine Oxidase from Cylindrocarpon didymum M–1

Sarcosine oxidase was purified to homogeneity from the cell extract of Cylindrocarpon didymum M–1, aerobically grown in medium containing choline as the carbon source. The molecular weight of the enzyme was estimated to be 45,000 by gel filtration method and 48,000 by the sodium dodecylsulfate disc gel electrophoresis method. The enzyme exhibited an absorption spectrum with maxima at 277 and 450 run and shoulders at 370 and 470 nm. The anaerobic addition of sarcosine to the enzyme resulted in the disappearance of the peak at 450 nm. The enzyme contained one mol of covalently bound FAD per mol of enzyme. Enzyme activity was inhibited by Ag⁺, Cu²⁺, Hg²⁺, p-chloromercuribenzoate and iodoacetate. The enzyme oxidized sarcosine but was inert toward choline, betaine, dimethylglycine and N-methyl amino acids. Km and V_max values for sarcosine were 1.8 ihm and 26.2 μmol/min/mg, respectively. The enzyme catalyzed the following reaction: Sarcosine+O₂+H₂O→glycine +formaldehyde+H₂O₂.     

Purification and properties of alcohol oxidase from Tanacetum vulgare

Alcohol oxidase (alcohol: O₂ oxidoreductase) from leaves of Tanacetum vulgare has been purified 5150-fold to homogeneity on disc electrophoresis and gel electrofocussing. The enzyme which is probably flavoprotein, has molecular weight 180 000 daltons and is comprised of two sub-units of 94 000 and 75 000 daltons. It is active over a broad range (pH 5–9) and best accepts primary aliphatic alcohols with 6 to 10 carbons, especially those with a 2-ene group. K_m values for hex-trans-2-ene-1-ol, geraniol (3,7-dimethylocta-trans-2,6-dien-1-ol) and n-octanol were 0.19, 1.56 and 0.49 mM respectively. The significance of the enzyme in the formation of leaf aldehyde (hex-trans-2-ene-1-al) and in terpene metabolism is discussed.     

Purification and characterization of oxalate oxidase from wheat seedlings

Oxalate oxidase (OxO, EC 1.2.3.4.) was purified to homogeneity from wheat (Triticum aestivum) seedlings by sequential thermal treatment, ultrafiltration, Sephadex G-100 gel filtration and affinity chromatography with concanavalin A. The enzyme was purified 66.11-fold with a recovery of 21.97%. It showed a subunit molecular mass of 32.6 kDa on SDS-PAGE and a native molecular mass of 170 kDa on Sephadex G-150 filtration, suggesting that it is a pentamer. The wheat OxO had a maximum activity at pH 3.5. Its K _m for oxalate was 0.21 mM. Chemical modification revealed that cysteine, lysine and carboxylate residues were essential for OxO activity, whereas arginine, serine, threonine and tryptophane residues were not essential.     

Purification and characterization of a glycolic acid (GA) oxidase active toward diglycolic acid (DGA) produced by DGA-utilizing Rhodococcus sp. No. 432

Diglycolic acid (DGA) oxidizing activity was found in crude extracts of Rhodococcus sp. no. 432 grown in DGA. Glycolic acid (GA) oxidase was purified approximately 80 times by treatment with streptomycin sulfate, precipitation with (NH₄)₂SO₄, chromatographies with DEAE-cellulose, DEAE-Toyopearl and Butyl-Toyopearl, and gel filtration on Toyopearl HW-55. The purified GA oxidase was almost homogeneous on sodium dodecyl sulfate (SDS) polyacrylamide gel electrophoresis. The purity was calculated to be more than 95%. The molecular weight of the enzyme, which appeared to consist of three identical units, was 158,000. Each subunit of GA oxidase included one molecule of FAD as a cofactor. The isoelectric point of the enzyme was around 5.3. GA oxidase was stable below 30°C and at the pH range of 6.0–8.5. The optimum pH and temperature were around 7.5 and 40°C, respectively. Oxygen, cytochrome c, ferricyanide and 2,6-dichlorophenol indophenol (DCIP) acted as an electron acceptor. The activity of GA oxidase was strongly inhibited by potassium cyanide, quinine, quinacrine, monoiodoacetate, 1,4-benzoquinone and some heavy metal ions. GA oxidase also had activity in DGA, GA, glyoxylic acid (GOA), methoxy acetate, ethoxy acetate and l-malate. Alcohols and other organic acids were not oxidized by the enzyme. The apparent K_m values for DGA, GA and GOA were about 26.7, 0.5 and 4.4 mM, respectively. The reaction products from DGA were supposed to be GOA and GA by the enzymatic assays. The reaction mechanism of GA oxidase in oxidation of DGA was supposed to be as follows: HOOCH₂COCH₂COOH+H₂O+acceptor→HOOCCHO+HOOCCH₂OH+ reduced acceptor.