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PubMed1986

The purification and properties of a cd-cytochrome nitrite reductase from Paracoccus halodenitrificans.

Paracoccus halodenitrificans, grown anaerobically in the presence of nitrite, contained membrane and cytoplasmic nitrite reductases. When assayed in the presence of phenazine methosulfate and ascorbate, the membrane-bound enzyme produced nitrous oxide whereas the cytoplasmic enzyme produced nitric oxide. When both enzymes were assayed in the presence of methyl viologen and dithionite, the cytoplasmic enzyme produced ammonia. Following solubilization, the membrane-bound enzyme behaved like the cytoplasmic enzyme, producing nitric oxide in the presence of phenazine methosulfate and ascorbate, and ammonia when assayed in the presence of methyl viologen and dithionite. The cytoplasmic and membrane-bound enzymes were purified to essentially the same specific activity. Only a single nitrite-reductase activity was detected on electrophoretic gels and the electrophoretic behavior of both enzymes suggested they were identical. The spectral properties of both enzymes suggested they were cd-type cytochromes. These data suggest that the products of nitrite reduction by the cd-cytochrome nitrite reductase are determined by the location of the enzyme and the redox potential of the electron donor.

Ammonia↗
PubMed1978

Studies on the optimalisation and standardisation of the light microscopical succinate dehydrogenase histochemistry.

The present investigation was undertaken in order to establish an optimal tissue pretreatment and an optimal incubation medium for the histochemical demonstration of succinate dehydrogenase (E.C. 1.3.99.1). The investigations were performed on steroid producing (testicle, adrenal gland) and steroid dependent (Fallopian tube) tissues. We studied the influences fo formalin fixation, acetone, magnesium ions, cyanides, electron carries (phenazine methosulfate, menadione coenzyme Q10), osmolarity, substrate concentration and inhibitors (oxalacetate, oxalate, malonate, 4-chloromercuribenzoic acid). The following procedure yields blameless morphological integrity and enzyme localization as well as optimal SDH-activity: Freezing of tissue cubes (diameter less than 5 mm) in propane cooled with liquid nitrogen or in melting freon. Incubation of 5 micrometer cryostat sections in narrow jars in the following medium (38.5 ml):--10 ml of 0.2 M sodium phosphate buffer pH 7.6 (52 mM).--18 mg tetranitro-BT in 0.5 ml dimethylformamide and aqua bidest. ad 10 ml (0.5 mM).--2.6 mg KCN in 16 ml aqua bidest. (1 mM).--540 mg succinate (disodium salt, hexahydrate) in 2 ml aqua bidest. (52 mM).--3 mg PMS (phenazine methosulfate) in 0.5 ml aqua bidest. (0.25 mM). The incubation medium has an osmolarity of 440 mosm. The incubation is carried out for 10 min at 37 degree C in darkness. To avoid non specific formazan deposits in lipid containing tissues a preincubation of the cryostat sections in 100% acetone at--22 degree C or--40 degree C for 7--10 min and an incubation time of 20--30 min is recommended. Control incubations adduced proof at the specificity of the SDH demonstration. Parallel incubation without PMS in order to determine indirectly the content of endogenous CoQ10 is further recommended.

Adrenal Glands↗
PubMed1984

Fluorescent redox dyes. 1. Production of fluorescent formazan by unstimulated and phorbol ester- or digitonin-stimulated Ehrlich ascites tumor cells.

The reduction of a new series of tetrazolium salts to red fluorescent formazans by Ehrlich ascites tumor cells is described. The qualitative effect on this reaction of two cell surface-active compounds and of six exogenous electron carriers was investigated by varying the incubation conditions. After incubation of Ehrlich ascites cells with the new colourless, water soluble 5-cyan-2.3-ditolyltetrazolium salts, bright red water-insoluble formazan crystals on the cell surface can be observed under fluorescence microscopy. The production of formazan is enhanced by 12-0-tetradecanoyl-phorbol-13-acetate (TPA) or digitonin (DIG), two potent stimulators of oxygen consumption or by the electron carriers phenazine methosulphate (PMS), 1-methoxy-phenazine methosulphate (MPMS), meldola blue (MB), methylene blue (MTB), and 2.6-dichlorindophenol (DCIP). These results provide further evidence for the existence of redox enzymes bound to the plasma membrane of intact ascites cells and for a free radical mechanism of tetrazolium salt reduction. The fluorescence property of the new redox dyes offers the advantage of high sensitivity. Moreover, their greater homogeneity relative to the commonly used di-tetrazolium salts lowers the chances of misinterpretations due to impurities. The possible application of these new mono-tetrazolium salts to cytochemical investigations of oxidative metabolic reactions is discussed.

Animals↗
PubMed1984

Diffusion during dehydrogenase reactions: the effects of intermediate electron acceptors.

A hamster cheek pouch model has been used to study the diffusion of reactants from the epithelium into adjacent muscle and connective tissue during the histochemical demonstration of glucose-6-phosphate dehydrogenase activity. The effects of the addition of intermediate electron acceptors to the incubation medium varied considerably from one acceptor to another, but were independent of the grade of polyvinyl alcohol incorporated into the medium. Menadione was the least effective intermediate both in transferring reducing equivalents from the primary dehydrogenase to Neotetrazolium chloride and in preventing diffusion. Phenazine methosulphate, Methylene Blue and Thionin were more efficient intermediates. Nevertheless, considerable diffusion occurred in the presence of Phenazine methosulphate, although very little diffusion was detectable with either of the thiazine dyes. It is suggested that these differences are related to different modes and sites of action of the carriers.

Animals↗
PubMed2004

Degradation pathway of 2-chloroethanol in Pseudomonas stutzeri strain JJ under denitrifying conditions.

The pathway of 2-chloroethanol degradation in the denitrifying Pseudomonas stutzeri strain JJ was investigated. In cell-free extracts, activities of a phenazine methosulfate (PMS)-dependent chloroethanol dehydrogenase, an NAD-dependent chloroacetaldehyde dehydrogenase, and a chloroacetate dehalogenase were detected. This suggested that the 2-chloroethanol degradation pathway in this denitrifying strain is the same as found in aerobic bacteria that degrade chloroethanol. Activity towards primary alcohols, secondary alcohols, diols, and other chlorinated alcohols could be measured in cell-free extracts with chloroethanol dehydrogenase (CE-DH) activity. PMS and phenazine ethosulfate (PES) were used as primary electron acceptors, but not NAD, NADP or ferricyanide. Cells of strain JJ cultured in a continuous culture under nitrate limitation exhibited chloroethanol dehydrogenase activity that was a 12 times higher than in cells grown in batch culture. However, under chloroethanol-limiting conditions, CE-DH activity was in the same range as in batch culture. Cells grown on ethanol did not exhibit CE-DH activity. Instead, NAD-dependent ethanol dehydrogenase (E-DH) activity and PMS-dependent E-DH activity were detected.

Aldehyde Oxidoreductases↗
PubMed2005

Effect of insulin on Ca(2+)-dependent hyperpolarization in erythrocytes from healthy donors and patients with type 2 diabetes mellitus accompanied by arterial hypertension.

Insulin decreased A23187-induced hyperpolarization of the erythrocyte membrane in healthy donors. These data indicate that insulin plays a role in the regulation of Ca(2+)-activated potassium channels in human erythrocytes. However, insulin had little effect on hyperpolarization response of cells induced by artificial ascorbate--phenazine methosulfate donor-acceptor system. Addition of insulin to cell suspension from patients with type 2 diabetes mellitus did not modulate hyperpolarization of the erythrocyte membrane induced by A23187 or ascorbate-phenazine methosulfate, which reflects impairment of regulatory mechanisms for Ca(2+)-activated potassium channels in erythrocytes.

Arteries↗
PubMed1985

Alternate putrescine metabolites: quantitative analysis of delta'-pyrroline oxidation to 2-pyrrolidone in tissue homogenates by high-pressure liquid chromatography.

A sensitive analytical procedure for following the oxidation of delta'-pyrroline to 2-pyrrolidone in tissue homogenates is described. Homogenates are extracted with chloroform/acetonitrile and fractionated by high-performance liquid chromatography, and 2-pyrrolidone is quantitated by monitoring the column effluent at 200 nm. The lower limit of 2-pyrrolidone that can be accurately (+/- 5%) quantitated is approximately 100 pmol. Phenazine methosulfate significantly enhances the rate of 2-pyrrolidone biosynthesis from delta'-pyrroline. Phenazine methosulfate and reduced glutathione are required to obtain proportionality between 2-pyrrolidone formation and incubation time. Formation of 2-pyrrolidone as a function of protein concentration is linear and 2-pyrrolidone biosynthesis as a function of delta'-pyrroline concentration is characterized by hyperbolic kinetics. Based on analysis of enzyme activity in different tissues, liver appears to play the dominant role in 2-pyrrolidone biosynthesis. The metabolic step from delta'-pyrroline to 2-pyrrolidone was localized in the cellular cytosol. These results demonstrate that the oxidation of delta'-pyrroline to 2-pyrrolidone is enzyme mediated and provide a useful method for further characterization of this metabolic step.

Animals↗
PubMed1975

Photophosphorylation and related properties of reaggregated vesicles from spinach photosystem I particles.

The small Photosystem I particles prepared from spinach chloroplasts by the action of Triton X-100 (TSF 1 particles) reaggregate into membrane structures when they are incubated with soybean phospholipids and cholate and then subjected to a slow dialysis. The membranes so formed are vesicular in nature and show the capability of catalyzing phenazine methosulfate-mediated cyclic photophosphorylation at rates which are usually about 20% of those observed with chloroplasts, but higher rates have been obtained. When coupling factor is removed from the chloroplasts by treatment with EDTA, a requirement for coupling factor can be shown for the subsequent ATP formation. The uncouplers carbonylcyanide 3-chlorophenyl-hydrazone, valinomycin, Triton X-100 and NH+4 are effective with the reformed vesicles, which do not show the typical light-induced pH gradient observed with chloroplasts. Incubation of the TSF 1 particles with phospholipids alone allows for the formation of membrane vesicles, but such vesicles are only slightly active in ATP formation. In most properties investigated, the reformed membrane vesicles resemble the original chloroplast membrane so far as phenazine methosulfate-mediated cyclic photophosphorylation is concerned, which indicates a high degree of selectivity in the reaggregation process. The major difference between chloroplasts and the reformed vesicles is the failure of the latter to show a light-induced pH gradient.

Cell Membrane↗
PubMed1976

Anthroyl stearate as a fluorescent probe of chloroplast membranes.

1. A reversible light-induced enhancement of the fluorescence of a "hydrophobic fluorophore", 12-(9-anthroyl)-stearic acid (anthroyl stearate), is observed with chloroplasts supporting phenazine methosulfate, cyclic or 1,1'-ethylene-2,2'-dipyridylium dibromide (Diquat) pseudo-cyclic electron flow; no fluorescence change is observed when methyl viologen or ferricyanide are used as electron acceptors. The stearic acid moiety of anthroyl stearate is important for its localization and fluorescence response in the thylakoid membrane, since structural analogs of anthroyl stearate lacking this group do not show the same response. 2. This effect is decreased under phosphorylating conditions (presence of ADP, Pi, Mg2+), and completely inhibited by the uncoupler of phosphorylation NH4Cl(5-10mM), as well as the ionophores nigericin and gramicidin-D (both at 5 - 10(-8)M). The MgCl2 concentration dependence of the anthroyl stearate enhancement effect is identical to that previously observed for cyclic photophosphorylation, as well as for the formation of a "high energy intermediate". The anthroyl stearate fluorescence enhancement is inhibited by increasing concentrations of ionophores in parallel with the decrease in ATP synthesis, but is essentially unaffected by specific inhibitors (Dio-9 and phlorizin) of photophosphorylation; thus, it appears that anthroyl stearate monitors a component of the "high energy state" of the thylakoid membrane rather than a terminal phosphorylation step. 3. The light-induced anthroyl stearate fluorescence enhancement is suggested to monitor a proton gradient in the energized chloroplast because (a) similar enhancement can be produced by sudden injection of hydrogen ions in a solution of anthroyl stearate; (b) when the proton gradient is dissipated by gramicidin or nigericin light-induced anthroyl stearate fllorescence is eliminated; (c) when the proton gradient is dissipated by tetraphenylboron, light-induced anthroyl stearate fluorescence decreases, and (d) light-induced anthroyl stearate fluorescence change as a function of pH is qualitatively similar to that observed with other probes for a proton gradient (e.g. 9-aminoacridine). Furthermore, anthroyl stearate does not monitor H+ uptake per se because (a) the pH dependence of H+ transport is different from that of the anthroyl stearate fluorescence change, and (b) tetraphenylboron, which does not inhibit H+ uptake, reduces anthroyl stearate fluorescence. Thus, anthroyl stearate appears to be a useful probe of a proton gradient supported by phenazine methosulfate of Diquat catalyzed electron flow and is the first "non-amine" fluorescence probe utilized for this purpose in chloroplasts.

Anthracenes↗
PubMed1976

Photoinactivation of photophosphorylation and dark ATPase in Rhodospirillum rubrum chromatophores.

Preillumination of Rhodospirillum rubrum chromatophores with strong, far-red light in the presence of phenazine methosulfate under non-phosphorylation conditions results in a selective, irreversible inactivation (typically about 70%) of photophosphorylation and of uncoupler-stimulated dark ATPase. The time course of the photoinactivation is similar to the light-on kinetics of the light-induced proton uptake in the absence of ADP. Only little photoinactivation occurs when the uncoupler carbonyl cyanide m-chlorophenyl hydrazone is present or when phenazine methosulfate is absent during the preillumination, indicating that the reaction occurs only when the membrane is energized. Phosphorylation conditions offer a practically complete protection against the photoinactivation. Inorganic phosphate, Mg2+ or ADP do not provide a significant protection against the photoinactivation, nor does ATP. The pH-dependence of the reaction(s) leading to photoinactivation may indicate that a partial reaction of the photophosphorylation process (perhaps only a conformational change of the coupling factor) precedes the photoinactivation.

Adenosine Diphosphate↗
PubMed1979

Localization and characterization of cytochromes from membrane vesicles of Escherichia coli K-12 grown in anaerobiosis with nitrate.

Cytochromes b of anaerobically nitrate-grown Escherichia coli cells are analysed. Ascorbate phenazine methosulfate distinguishes low and high potential cytochromes b. Reduction kinetics performed at 559 nm presents a very complex pattern which can be analysed assuming that at least four b-type cytochromes are present. The electron transport chain from formate to oxygen would contain a low potential cytochrome b-556, a cytochrome b-558 associated to the oxidase, and a cytochrome d as the principle oxidase. Cytochrome o is also present, but seems to be functional only at low oxygen concentrations. A cytochrome b-556 associated to nitrate reductase is shown to belong to a branch of the formate-oxidase chain. 2-N-Heptyl-4-hydroxyquinoline-N-oxide affects the reduction kinetics in a very complex way. One inhibition site is in evidence between cytochrome b-558 and cytochrome d; another between the cytochrome associated to nitrate reductase and the nitrate reductase. A third inhibition site is located in the common part of the formate-nitrate and the formate-oxidase systems. Ascorbate phenazine methosulfate is shown to donate electrons near cytochrome b-558.

Anaerobiosis↗
PubMed1979

Reduction of nitrite to nitrous oxide by a cytoplasmic membrane fraction from the marine denitrifier Pseudomonas perfectomarinus.

A cytoplasmic membrane fraction from the marine denitrifier Pseudomonas perfectomarinus reduced nitrite to nitrous oxide in a stoichiometric reaction without nitric oxide as free intermediate. The membrane system had a specific requirement for FMN with NAD(P)H as electron donors. Other electron donors were ascorbate-reduced cytochrome c-551 or phenazine methosulfate. The membrane fraction contained tightly bound cytochrome cd which represented only a small portion of the total cytochrome cd of the cell. As further terminal oxidase cytochrome o was identified. The membrane fraction produced also nitrous oxide from nitric oxide, however, at a substantially lower rate than from nitrite when using ascorbate-reduced phenazine methosulfate as electron donor.

Cell Membrane↗
PubMed1979

The influence of energy-transfer inhibitors on proton permeability and photophosphorylation in normal and preilluminated Rhodospirillum rubrum chromatophores.

(1) Chromatophores were preilluminated in the presence of phenazine methosulphate or diaminodurene, and without phosphorylation substrates; next they were transferred to fresh medium and assayed for light-induced proton uptake, light-induced 9-aminoacridin fluorescence quenching, and photophosphorylation. (2) Preillumination in the presence of phenazine methosulphate or diaminodurene causes an inhibition of the photophosphorylation rate. The presence of ADP + MgCl2 + phosphate, or ADP + MgCl2 + arsenate during preillumination provides full protection against this effect. (3) Preilluminated chromatophores are leaky for protons. The leak is expressed as an accelerated dark decay, and a diminished extent of succinate-supported, light-induced proton uptake. The extent of light-induced 9-aminoacridin fluorescence quenching is also diminished. (4) The proton leak can be closed by oligomycin and by dicyclohexyl carbodiimide (at concentrations similar to those used to inhibit photophosphorylation), but not by aurovertin. Closure of the proton leak results in partial restoration of the photophosphorylation rate. (5) The inhibition of phosphorylation by oligomycin or dicyclohexyl carbodiimide is time-dependent. In untreated chromatophores, the time-dependence is determined by the extent of membrane energization. In preilluminated chromatophores, the time-dependence is determined in addition by the extent to which the proton leaks have been closed. The reasons for this are briefly discussed.

Antimycin A↗
PubMed1979

Studies on the succinate dehydrogenating system. I. Kinetics of the succinate dehydrogenase interaction with a semiquindiimine radical of N,N,N',N'-tetramethyl-p-phenylenediamine.

1. The activities of the soluble reconstitutively active succinate dehydrogenase (EC 1.3.99.1) measured with three artificial electron acceptors, e.g. ferricyanide, phenazine methosulfate and free radical of N,N,N',N'-tetramethyl-p-phenylenediamine (WB), have been compared. The values estimated by extrapolation to infinite acceptor concentration using double reciprocal plots 1/v versus 1/[acceptor] are nearly the same for ferricyanide and phenazine methosulfate and about twice as high for the WB. 2. The double reciprocal plots 1/v versus 1/[succinate] in the presence of malonate at various concentrations of WB give a series of straight lines intercepting in the third quadrant. The data support the mechanism of the overall reaction, in which the reduced enzyme is oxidized by WB before dissociation of the enzyme-product complex. 3. The dependence of the rate of the overall reaction on WB concentration shows that only one kinetically significant redox site of the soluble succinate dehydrogenase is involved in the reduction of WB. 4. Studies of the change of V and Km values during aerobic inactivation of the soluble enzyme suggest that only 'the low Km ferricyanide reactive site' (Vinogradov, A.D., Gavrikova, E.V. and Goloveshkina, V.G. (1975) Biochem. Biophys, Res. Commun. 65, 1264--1269) is involved in reoxidation of the reduced enzyme by WB. 5. The pH dependence of V for the succinate-WB reductase reaction shows that the group of the enzyme with the pKa value of 6.7 at 22 degrees C is responsible for the reduction of dehydrogenase in the enzyme-substrate complex. 6. When WB interacts with the succinate-ubiquinone region of the respiratory chain, the double reciprocal plot 1/v versus 1/[WB] gives a straight line. The thenoyltrifluoroacetone inhibition of succinate-ubiquinone reductase or extraction of ubiquinone alter the 1/v versus 1/[WB] plots for the curves with a positive initial slope intercepting the ordinate at the same V as in the native particles. The data support the mechanism of succinate-ubiquinone reduction, in which no positive modulation of succinate dehydrogenase by ubiquinone exist in the membrane.

Aerobiosis↗
PubMed1978

Phosphate transport in membrane vesicles from Escherichia coli.

Escherichia coli strain AN710 possesses only the PIT system for phosphate transport. Membrane vesicles from this strain, which contain phosphate internally, perform exchange and active transport of phosphate. The energy for active transport is supplied by the respiratory chain with ascorbate phenazine methosulphate as electron donor. To a lesser extent also the oxidation of D-lactate energizes phosphate transport; the oxidation of succinate is only marginally effective. Phosphate transport is driven by the proton-motive force and in particular by the pH gradient across the membrane. This view is supported by the observation that phosphate transport is stimulated by valinomycin, inhibited by nigericin and abolished by the uncoupler carbonyl cyanide m-chlorophenylhydrazone. Neither inhibitor affects phosphate exchange. The phosphate analogue arsenate inhibits both the exchange reaction and active transport. Both processes are stimulated by K+ and Mg2+, the highest activities being observed with both ions present. Membrane vesicles have also been isolated from Escherichia coli K10, a strain which possesses only a functional PST phosphate transport system. These vesicles perform neither exchange nor active transport of phosphate, although active transport of amino acids is observed in the presence of ascorbate-phenazine methosulphate or D-lactate.

Bacteriolysis↗
PubMed1980

Energization of amino acid transport in energy-depleted Ehrlich cells and plasma membrane vesicles.

We redirect attention to contributions to the energization, of the active transport of amino acids in the Ehrlich cell, beyond the known energization, by down-gradient comigration of Na+, beyond possible direct energization by coupling to ATP breakdown, and beyond known energization by exchange with prior accumulations of amino acids. We re-emphasize the uphill operation of System L, and by prior depletion of cellular amino acids show that this system must receive energy beyond that made available by their coupled exodus. After this depletion the Na+-indepdendent accumulation of the norbornane amino acid, 2-aminobicycloheptane-2-carboxylic acid becomes strongly subject to stimulation by incubation with glucose. Energy transfer between Systems A and L through the mutual substrate action of ordinary amino acids was minimized although not entirely avoided by the use of amino acid analogs specific to each system. When 2,4-dinitrophenol was included in the depleting treatment, and pyruvate, phenazine methosulfate, or glucose used for restoration, recovery of uptake of the norbornane amino acid was independent of external Na+ or K+ levels. Restoration or the uptake of 2-(methylamino)isobutyric acid was, however, decreased by omission of external K+. Contrary to an earlier finding, restoration of uptake of each of these amino acids was associated with distinct and usually correlated rises in cellular ATP levels. ATP addition failed to stimulate exodus of the norbornane amino acid from plasma membrane vesicles, although either NADH or phenazine methosulfate did stimulate exodus. ATP production and use is thus associated with transport energization although evidence for a direct role failed to appear.

Adenosine Triphosphate↗
PubMed1975

Nothing dehydrogenase reaction as an artefact in serum isoenzyme analyses.

A nonspecific staining occurs in serum in isoenzyme methods based on tetrazolium staining reactions. The artefact is pronounced when a large application volume, a prolonged incubation time, distinctly alkaline conditions, or excess of phenazine methosulphate is used. Only phenazine methosulphate and a tetrazolium stain are required for the appearance. Inhibition studies and histochemical staining reactions give evidence that protein-bound sulphydryl groups are responsible for the artefact in serum.

Chloromercuribenzoates↗
PubMed1990

Purification and characterization of 3-ketosteroid-delta 1-dehydrogenase from Nocardia corallina.

The inducible 3-ketosteroid-delta 1-dehydrogenase of Nocardia corallina which catalyzes the introduction of a double bond into the position of carbon 1 and 2 of ring A of 3-ketosteroid has been obtained in four steps with a 50% yield and 360-fold purification. The enzyme is homogeneous as judged by SDS-gel electrophoresis and is a monomeric protein with a molecular weight of 60,500. The isoelectric point of the enzyme is about 3.1. The enzyme contains 1 mol of flavin adenine dinucleotide per mol of protein, and has a typical flavoprotein absorption spectrum with maxima of 458, 362 and 268 nm. The enzyme is very stable in the absence of added cofactors, and catalyzes the dehydrogenation of delta 4-3-ketosteroids in the presence of phenazine methosulfate, which acts as an excellent electron acceptor. Potassium ferricyanide and cytochrome c did not act as electron acceptors. The delta 1-dehydrogenation was also stimulated by molecular oxygen with stoichiometric production of hydrogen peroxide and delta 1,4-3-ketosteroid. The optimum pH is 10 for dehydrogenation using phenazine methosulfate, and is between 8.5 and 10 for the oxidase reaction. The enzyme oxidizes a wide variety of 3-ketosteroids, but not 3 beta-hydroxysteroids. 3-Ketosteroids having an 11 alpha- or 11 beta-hydroxyl group were oxidized at slow rates. The purified enzyme catalyzes efficiently aromatization of the A-ring of 19-nortestosterone and 19-norandrostenedione to produce estradiol and estrone. 19-Hydroxytestosterone, 19-hydroxyandrostenedion and 19-oxotestosterone were converted to the respective phenolic steroids with cleavage of the C10 side-chain. Activities of 3-ketosteroid-delta 4-dehydrogenase, delta 5-3-ketosteroid-4,5-isomerase, 3 beta-hydroxysteroid dehydrogenase and 17 beta-hydroxysteroid dehydrogenase were not observed in the purified preparations. Properties of this novel flavoprotein enzyme are discussed.

Amino Acids↗