Purification and properties of cytochrome b-562.5 from Ulva pertusa.

Cytochrome b-562.5 (Ulva pertusa) was extracted from a green alga, U. pertusa, by homogenization of the thalli in phosphate buffer solution. Purification was carried out by acrinol treatment, ammonium sulfate fractionation, DEAE-cellulose and DEAE-Sephadex column chromatographies, and Sephadex gel filtration. Cytochrome b-562.5 has absorption maxima at 562.5 (alpha), 530.5 (beta), 429 (gamma), and 326 nm (delta) in the reduced form and at 537, 415 (gamma), and 275 nm in the oxidized form. The alpha-band of the reduced form is asymmetric with a shoulder at 560 nm, at liquid nitrogen temperature this band splits into two distinct peaks at 562 and 556.5 nm. The absorption maxima of the pyridine ferrohemochrome appear at 556 (alpha), 523 (beta), and 418 nm (gamma). The cytochrome does not combine with carbon monoxide or cyanide. The preparation of the cytochrome shows little peroxidase activity. The cytochrome is oxidized by ferricyanide and reduced by cysteine, ascorbate, and hydrosulfite. Autoxidation of the cytochrome was found to be very slow. The midpoint potential (Em) of the cytochrome was determined by equilibration with the ferro- and ferri-EDTA system to be +0.20 V at pH7.0. The molecular weight of the cytochrome was estimated by Sephadex gel filtration to be 23x10(3).     

Studies on cytochrome c oxidase, VII. Isolation and chemical characterization of polypeptide VII.

Polypeptide VII of cytochrome c oxidase was isolated and purified by gel filtration on Bio-Gel P-10 in 10% acetic acid. Automatic Edman degradation of this peptide chain was not successful, because it is blocked at the N-terminus. The amino acid analysis shows a relatively high content of hydrophilic residues (54%). On the basis of this analysis and the apparent molecular weight by sodium dodecyl sulfate gel electrophoresis and gel filtration, a chain length of about 80 residues was calculated. Among the tryptic peptides one blocked heptapeptide was found. Cleavage of this peptide with thermolysin gave two peptide fragments, one of which was not retained on a cation exchange resin. Mass spectrometric sequence determination of this peptide revealed the structure Ac-Ala-Glu-Asp for the N-terminus of polypeptide VII. Treatment with carboxypeptidase A at two different pH values showed that the C-terminal amino acid is isoleucine and the penultimate amino acid is lysine.     

Purification and characterization of a heme-containing amine dehydrogenase from Pseudomonas putida.

The primary amine dehydrogenase of Pseudomonas putida NP was purified to homogeneity as judged by polyacrylamide gel electrophoresis. Cytochrome c or an artificial electron acceptor was required for amine dehydrogenase activity. The enzyme was nonspecific, readily oxidizing primary monoamines, benzylamine, and tyramine; little or no measurable activity was detected with isoamines, L-ornithine, L-lysine, and certain diamines or polyamines. The pH optima for n-butylamine, benzylamine, and n-propylamine were 7.0, 6.5, and 7.0, respectively. The molecular weight of the enzyme was 112,000 as determined by gel filtration and 95,300 as analyzed by sedimentation equilibrium. Subunit analysis by sodium dodecyl sulfate gel electrophoresis suggested that the enzyme was composed of two nonidentical subunits with molecular weights of 58,000 and 42,000. The absorption spectrum of the purified enzyme was indicative of a hemoprotein, exhibiting absorption maxima at 277, 355, and 408 nm. Reduction with sodium dithionite or amine substrates resulted in absorption maxima at 523 and 552 nm and a shift in the Soret peak to 416 nm. These results suggested that the enzyme is a hemoprotein of the type c cytochrome. There was no evidence that flavins were present.     

Characterization of cytochrome c3 from the thermophilic sulfate reducer Thermodesulfobacterium commune

A c3 type cytochrome has been purified from the thermophilic, non-spore-forming, sulfate-reducing bacterium Thermodesulfobacterium commune. The purified protein was homogeneous as judged by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, gel filtration, and isoelectric focusing. A pI of 6.83 was observed. The molecular weight of the cytochrome was estimated to be ca. 13,000 from both gel filtration and sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The hemoprotein exhibited absorption maxima at 530, 408.5, and 351 nm in the oxidized form and 551.5 (alpha band), 522.5 (beta band), and 418.5 nm (gamma band) in the reduced form. The extinction coefficients of T. commune cytochrome c3 were 130,000, 74,120, and 975,000 M-1 cm-1 at 551.5, 522.5, and 418.5 nm, respectively. It contains four hemes per molecule, on the basis of both the iron estimation and the extinction coefficient value of its pyridine hemochrome. The amino acid composition showed the presence of eight cysteine residues involved in heme binding. T. commune cytochrome c3 had low threonine, serine, and glycine contents and high glutamic acid and hydrophobic residue contents. The electrochemical study of T. commune cytochrome c3 by cyclic voltammetry and differential pulse polarography has shown that the cytochrome system behaves like a reversible system. Four redox potential values at Eh1 = -0.140 +/- 0.010 V, Eh2 = Eh3 = Eh4 = -0.280 +/- 0.010 V have been determined. T. commune cytochrome c3, which acts as the physiological electron carrier of hydrogenase, is similar in most respects to the multiheme low-potential cytochrome c3 which is characteristic of the genus Desulfovibrio.     

Purification and properties of trimethylamine N-oxide reductase from aerobic photosynthetic bacterium Roseobacter denitrificans.

Trimethylamine N-oxide (TMAO) reductase was purified from an aerobic photosynthetic bacterium Roseobacter denitrificans. The enzyme was purified from cell-free extract by ammonium sulfate fractionation, DEAE ion exchange chromatography, hydrophobic chromatography, and gel filtration. The purified enzyme was composed of two identical subunits with molecular weight of 90,000, as identified by SDS-polyacrylamide gel electrophoresis, containing heme c and a molybdenum cofactor. The molecular weight of the native enzyme determined by gel filtration was 172,000. The midpoint redox potential of heme c was +200 mV at pH 7.5. Absorption maxima appeared at 418,524, and 554 nm in the reduced state and 410 nm in the oxidized state. The enzyme reduced TMAO, nicotine acid N-oxide, picoline N-oxide, hydroxylamine, and bromate, but not dimethyl sulfoxide, methionine sulfoxide, chlorate, nitrate, or thiosulfate. Cytochrome c2 served as a direct electron donor. It probably catalyzes the electron transfer from cytochrome b-c1 complex to TMAO reductase. Cytochrome c552, another soluble low-molecular-weight cytochrome of this bacterium, also donated electrons directly to TMAO reductase.     

Some properties and amino acid sequence of plastocyanin from a green alga, Ulva arasakii

Plastocyanin was purified from a multicellular, marine green alga, Ulva arasakii, by conventional methods to homogeneity. The oxidized plastocyanin showed absorption maxima at 252, 276.8, 460, 595.3, and 775 nm, and shoulders at 259, 265, 269, and 282.5 nm; the ratio A276.8/A595.3 was 1.5. The midpoint redox potential was determined to be 0.356 V at pH 7.0 with a ferri- and ferrocyanide system. The molecular weight was estimated to be 10,200 and 11,000 by SDS-PAGE and by gel filtration, respectively. U. arasakii also has a small amount of cytochrome c6, like Enteromorpha prolifera. The amino acid sequence of U. arasakii plastocyanin was determined by Edman degradation and by carboxypeptidase digestion of the plastocyanin, six tryptic peptides, and five staphylococcal protease peptides. The plastocyanin contained 98 amino acid residues, giving a molecular weight of 10,236 including one copper atom. The complete sequence is as follows: AQIVKLGGDDGALAFVPSKISVAAGEAIEFVNNAGFPHNIVFDEDAVPAGVDADAISYDDYLNSKGETV VRKLSTPGVY G VYCEPHAGAGMKMTITVQ. The sequence of U. arasakii plastocyanin is closet to that of the E. prolifera protein (85% homology). A phylogenetic tree of five algal and two higher plant plastocyanins was constructed by comparing the amino acid differences. The branching order is considered to be as follows: a blue-green alga, unicellular green algae, multicellular green algae, and higher plants.     

Thiobacillus ferrooxidans cytochrome c-552: purification and some of its molecular features

Soluble cytochrome c-552 was purified from Thiobacillus ferrooxidans to an electrophoretically homogeneous state. The cytochrome showed absorption peaks at 276, 411 and 523 nm in the oxidized form and peaks at 315, 417, 523 and 552 nm in the reduced form. The molecular weight of the cytochrome was estimated to be 13,800 on the basis of the amino acid composition and heme content, and 14,000 from SDS-polyacrylamide gel electrophoresis analysis. Its midpoint redox potential at pH 7.0 was determined to be +0.36 V. The N-terminal amino acid sequence of the cytochrome was determined as follows: A-G-G-A-G-G-P-A-P-Y-R-I-S-?-D-?-M-V-?-S-G-M-P-G-. Ferrocytochrome c-552 was oxidized by the membrane fraction of T. ferrooxidans, and the oxidation rate was more rapid at pH 3.0 than at pH 6.5. Ferricytochrome c-552 was reduced by Fe(II)-cytochrome c oxidoreductase with Fe2+ at pH 3.5, while horse ferricytochrome c was not reduced by the enzyme under the same reaction conditions.     

A Candida albicans metallopeptidase degrades constitutive proteins of extracellular matrix

A soluble c-type cytochrome was first purified from Geobacter metallireducens to an electrophoretically homogeneous state. The purified cytochrome c showed absorption peaks at 530 and 409 nm in the oxidized form and 552, 522, and 418 nm in the reduced form. Polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate allowed us to calculate the molecular mass at 9.5 kDa. It contained 3 mol of heme c per molecule of the protein on the basis of heme c and protein concentration. The mid-point redox potential at pH 7.0 was determined to be -190 mV. Although the N-terminal amino acid sequence of the first 17 residues was similar to that of Desulfuromonas acetoxidans cytochrome c7, G. metallireducens cytochrome c did not show Fe(III)-reducing activity.     

Mycoplasma Phosphoenolpyruvate-Dependent Sugar Phosphotransferase System: Purification and Characterization of Enzyme I

The Mycoplasma phosphoenolpyruvate-dependent sugar phosphotransferase system consists of three components: a membrane-bound enzyme II, a soluble phosphocarrier protein (HPr), and a soluble enzyme I. The soluble enzyme I was purified by ammonium sulfate fractionation; Bio-Gel P-10 gel filtration; acid precipitation; diethylaminoethyl-Bio-Gel A; and Bio-Gel HTP column chromatography. The enzyme I was shown to be homogeneous by electrophoresis in a pH 8.9 non-sodium dodecyl sulfate gel and by isoelectric focusing. Whereas the protein moved as a single component in both the non-sodium dodecyl sulfate gel and isoelectric focusing, on sodium dodecyl sulfate gels, it moved as three subcomponents. The molecular weights of the three subunits, alpha, beta, and gamma, were 44,500, 62,000 and 64,500, respectively. The holoprotein moved as a single component, in the region of 220,000 daltons, in a Bio-Gel A 0.5-agarose column. The molar ratio of subunits was estimated to be 2alpha:1beta:1gamma. The elution characteristics on a diethylaminoethyl column at pH 7.4 and 6.8, acid precipitation data, and amino acid composition indicated that the protein is acidic. Isoelectric focusing occurred at pH 4.8. N-terminal amino acids determined by the dansyl chloride method indicated that glycine, alanine, and tyrosine are N-terminal amino acids of the three subunits. Although the protein was stable for at least 14 months at -20 degrees C, it was irreversibly inactivated by the thiol reagent N-ethyl-maleimide.     

The polypeptide composition of ubiquinone-cytochrome c reductase (complex III) from beef heart mitochondria.

The subunit structure of ubiquinone-cytochrome c reductase (complex III) has been examined and eight different polypeptides have been identified. Apparent molecular weights for each have been obtained by one or more methods including polyacrylamide gel electrophoresis in sodium doecyl sulfate and in sodium dodecyl sulfate-8 M urea and by gel filtration in sodium dodecyl sulfate and in 6 M guanidine hydrochloride. Values obtained are as follows: I, 47 500; II, 45 500; III, 29 500; IV, 27 800; V, 24 800; VI, 13 900; VII, 10 700; VIII, 4 800-9 00. Individual polypeptides have been purified and the amino acid composition of several of these have been determined. At least one polypeptide, the apoprotein of cytochrome b, is hydrophobic in character and this is a mitochondrially synthesized component (B. Lorenz, W. Kleinow, and H. Weiss (1974), Hoppe-Seyler's Z. Physiol. Chem. 355, 300). Other polypeptides including the hemoprotein of cytochrome c1 are more hydrophilic in amino acid composition.     

Characterization of NADH-cytochrome c reductase, a component of benzoate 1,2-dioxygenase system from Pseudomonas arvilla c-1.

NADH-cytochrome c reductase, a component of benzoate 1,2-dioxygenase system, was purified to homogeneity, as judged by sodium dodecyl sulfate disc gel electrophoresis and ultracentrifugation, from benzoate-induced cells of Pseudomonas arvilla. The molecular weight of the enzyme was determined to be 38,300 by sedimentation equilibrium analysis, 37,000 by Sephadex G-100 gel filtration, and 37,500 by sodium dodecyl sulfate disc gel electrophoresis, respectively, indicating that the enzyme consisted of a single polypeptide chain. The sedimentation coefficient was calculated to be 3.3 S. The Stokes radius for the enzyme was calculated to be 27 A. The isoelectric point of the enzyme was estimated to be pH 4.2. The enzyme contained 1 mol of FAD, 2 mol of iron, and 2 mol of labile sulfide/mol of enzyme. It exhibited absorption spectrum with maxima at 273, 340, 402, and 467 nm. Amino acid analysis of the enzyme revealed that it was devoid of tryptophan. The enzyme contained 9 mol of cysteine/mol of enzyme but no disulfide linkage. The turnover number of the enzyme for the NADH-dependent reduction of cytochrome c was 17,100 at 24 degrees C. Although NADPH also acted as an electron donor, NADH was highly superior to NADPH. Ferricyanide and 2,6-dichlorophenolindophenol served as electron acceptors. Certain other properties of the enzyme are also presented.     

Characterization and amino acid sequences of cytochromes c6 from two strains of the green alga Chlorella vulgaris

Cytochromes c6 from the green algae Chlorella vulgaris CK-5 (CK5cyc6) and C. vulgaris CK-22 (CK22cyc6) were characterized and their amino acid sequences were analyzed. CK5cyc6 had a molecular mass of 9.3 kDa, isoelectric points of 3.0 (reduced) and 3.6 (oxidized), and a redox potential of +362 mV at pH 7.0. CK22cyc6 had a molecular mass of 9.5 kDa, isoelectric points of 2.9 (reduced) and 3.5 (oxidized), and a redox potential of +355 mV at pH 7.0. The absorption spectra of both cytochromes c6 showed 4 maxima in reduced form, and 2 maxima and a weak peak at 695 nm in oxidized form. The pyridine ferrohemochrome spectra indicated that their prosthetic group was heme c. These physicochemical properties were similar to those of other algal cytochromes c6. The amino acids (88 residues) of CK5cyc6 and CK22cyc6 were sequenced and the sequence motif -CXXCH-, which is typical of the heme-binding site of c-type cytochrome, was clearly confirmed in both cytochromes. Twenty-six amino acid residues were substituted, and the similarity score of each of them was 70.45%.     

Isolation and characterization of growth hormone from a marine fish, bonito (Katsuwonus pelamis)

Growth hormone (GH) was extracted under alkaline conditions (pH 10) from pituitary glands (6.3 g) of bonito (Katsuwonus pelamis), and subsequently purified by gel filtration, ion exchange chromatography, and reversed-phase HPLC. The GH was monitored by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and by immunoblotting with yellowtail GH antiserum at each step of purification. GH activity was determined by an in vivo bioassay. The yield of this hormone was 4.8 mg/g wet tissue. Intraperitoneal injection of bonito GH at doses of 0.1 and 1 micrograms/g body wt at 7-day intervals resulted in a significant increase in body weight and length of juvenile rainbow trout. Bonito GH antiserum exhibited both species and hormone specificity in radioimmunoassay. However, the bonito GH antiserum as well as yellowtail GH antiserum exhibited hormone specificity but not species specificity in immunoblotting. A molecular weight of 21,000 and an isoelectric point of 7.0 for bonito GH were estimated by SDS-PAGE and gel electrofocusing, respectively. The complete amino acid sequence of 185 residues was determined by sequencing fragment peptides prepared by chemical and enzymatic cleavages. Sequence comparison of bonito GH with other GHs revealed that there is a significant deletion in the middle of the molecule.     

Purification and properties of the urea amidolyase from Candida utilis.

Urea amidolyase was purified to homogeneity from extracts of Candida utilis. The purification involves protamine sulfate precipitation, ammonium sulfate precipitation, polyethylene glycol precipitation, Sepharose 6B gel filtration, DEAE-cellulose column chromatography, and hydroxylapatite column chromatography. The final preparation is pure as judged by disc-gel electrophoresis. The molecular weight of urea amidolyase, as determined by gel filtration and disc-gel electrophoresis, is between 500,000 and 520,000. Treatment with sodium dodecyl sulfate results in two peptides with molecular weights of 70,000 and 170,000. The urea carboxylase and allophanate hydrolase activities of urea amidolyase may be distinguished from one another on the basis of (a) the effect of the stabilizers, urea and glycerol, (b) the effect of storage pH on activity, and (c) selective inhibition by sulfhydryl reagents.     

Highly purified hydroxylamine oxidoreductase derived from Nitrosomonas europaea. Some physicochemical and enzymatic properties.

Hydroxylamine oxidoreductase [EC 1.7.3.4] of Nitrosomonas europaea was purified to an electrophoretically homogeneous state and some of its properties were studied. The molecular weight of the enzyme as determined by gel filtration on Sephadex G150 and by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate is 175,000-180,000, while the minimum molecular weight per heme determined from the dry weight and heme content is 17,500. The enzyme is a C-type cytochrome; its reduced form shows absorption peaks at 418 (gamma peak), 521 (beta peak), 553 (alpha peak), and 460 nm (due to an unidentified chromophore). Although the alpha peak at 553 nm has a shoulder at 559 nm, the enzyme does not posses protoheme or a cytochrome b subunit. It seems likely that the enzyme molecule possess heme c molecules in different states. The enzyme reacts rapidly with various eukaryotic cytochromes c, but does not react with "bacterial-type" cytochromes c. Although the enzyme does not react with cytochrome c-552 (N. europaea), another C-type cytochrome of the organism, cytochrome c-554 (N. europaea) acts as an electron acceptor for the enzyme.     

The proteolytic system of Penicillium roqueforti. V. -- Purification and properties of an alkaline aminopeptidase.

An alkaline aminopeptidase was isolated from the culture medium of Penicillium roqueforti. The enzyme was purified by ammonium sulfate precipitation, filtration on Bio-Gel P-100, chromatography on D.E.A.E.-cellulose and hydroxylapatite, filtration on Bio-Gel P-150 and electrofusing. The purified preparation was homogeneous on polyacrylamide gel electrophoresis at pH 8.5. The molecular weight of the enzyme was estimated to be about 35,000 daltons. The isoelectric point is 4.5. The optimum pH for L-leucine-p-nitroanilide hydrolysis is 8.0. At 35 degrees C the enzyme is stable between pH 6.0 and 7.0. Ethylenediamine tetraacetic acid and a sulfhydryl reagent (p-hydroxymercuribenzoate) inhibit the activity, but the enzyme is insensitive to diisopropylfluorophosphate. Hydrolysis of synthetic peptides shows that the enzyme releases apolar amino acids. Dipeptides are poorly hydrolyzed and Gly in penultimate or N-terminal position causes poor activity. The enzyme is able to cleave the N-terminal Arg-Pro bond of bradykinin.     

Studies on cytochrome c oxidase, VIII. The amino acid sequence of polypeptide VII.

The sequence determination of polypeptide VII from beef heart cytochrome c oxidase is described. The amino acid sequence is deduced from overlapping tryptic peptides and peptides obtained after cleavage with Staphylococcus aureus protease. The protein consists of 85 amino acids corresponding to a Mr of 10026, in agreement with a value of 9500 obtained by sodium dodecyl sulfate gel electrophoresis. The amino acid sequence around the only methionine present is very similar to sequences around the invariant heme binding methionine of the cytochrome c family. This similarity suggests that the protein is one of the heme bindings subunits of the oxidase.     

Proline iminopeptidase from Bacillus megaterium: purification and characterization

Proline iminopeptidase [EC 3.4.11.5] was purified about 1,700-fold from cell free extract of Bacillus megaterium by a series of column chromatographies on DEAE-Toyopearl, PCMB-T-Sepharose and hydroxyapatite, and gel filtration on Toyopearl FW-55. The purified enzyme still contained a minor contaminant as judged by disc gel electrophoresis. The enzyme was most active at pH 7.0 with Pro-beta-naphthylamide (Pro-2-NNap) as the substrate, and hydrolyzed Pro-X (X = amino acid, peptide, amide, and arylamide) bonds when the proline residue was at the amino terminal. The enzyme was completely inactivated by p-chloromercuribenzoate (PCMB), but was not inhibited by metal chelators, diisopropylphosphorofluoridate (DFP) and phenylmethanesulfonyl fluoride (PMSF). The enzyme inactivated with PCMB was reactivated by adding 2-mercaptoethanol. From this result and the chromatographic profile on PCMB-T-Sepharose, the enzyme seems to be a sulfhydryl enzyme. The isoelectric point of the enzyme was 4.0. The molecular weight of the enzyme was estimated to be 58,000 by gel filtration on Toyopearl and 60,000 by sodium dodecyl sulfate (SDS) gel electrophoresis, suggesting that the enzyme is a monomer.     

Some properties and occurrence of cytochrome c-552 in the aerobic photosynthetic bacterium Roseobacter denitrificans

Characteristics and occurrence of cytochrome c-552 from an aerobic photosynthetic bacterium, Roseobacter denitrificans, were described.Relative molecular mass of the cytrochrome was 13.5 kDa on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and 15,000 by gel filtration. This cytochrome was a acidic protein having a pI of 5.6 and E_m was +215 mV at pH 7.0. Absorption peaks were at 278, 408 and 524 nm in the oxidized form and 416, 523 and 552 nm in the reduced form.Amino acid composition and N-terminal amino acid sequence of cytochrome c-552 determined for 24 residues had low similarities to those of cytochrome c-551 of this bacterium, which is homologous to cytochrome c ₂, although the physico-chemical properties of these two cytochromes were similar to each other.Cytochrome c-552 was maximally synthesized in the light under aerobic conditions but not in the dark. The synthesis also occurred in the presence of alternative acceptors such as trimethylamine N-oxide (TMAO) and nitrate under anaerobic conditions. Our results suggest that cytochrome c-552 is involved in TMAO respiration and denitrification in R. denitrificans, although the effect of light remains to be solved.Abbreviations E_m Midpoint redox potential - PAGE Polyacrylamide ge electrophoresis - SDS-PAGE Sodium dodecyl sulfate polyacrylamide gel electrophoresis - TMAO Trimethylamine N-oxide     

Prolidase from bovine intestine: purification and characterization

Prolidase [iminodipeptidase, EC 3.4.13.9] was highly purified from the cytosol fraction of bovine small intestine by a series of column chromatographies on DEAE-Toyopearl, Sephadex G-150, PCMB-T-Sepharose and hydroxyapatite. The purified enzyme appeared homogeneous as judged by disc gel electrophoresis. The enzyme was most active at pH 7.2 with Gly-Pro as substrate. It was stable between pH 5.5 and 8.5 for 30 min at 30 degrees C and retained half of the activity after 15 min at 40 degrees C. It was completely inactivated by p-chloromercuribenzoate (PCMB) but not inhibited by diisopropylphosphorofluoridate (DFP), phenylmethane sulfonylfluoride (PMSF) and metal chelators. Its amino acid composition was determined. Its molecular weight was estimated to be 116,000 by gel filtration on Sephadex G-150 and 56,000 by sodium dodecyl sulfate (SDS) gel electrophoresis, suggesting that it is a dimer. It hydrolyzed dipeptides represented as X-Pro (X = amino acid).