Reaktionen der Hydrogenase aus Rhodopseudomonas capsulata im partikelgebundenen und gelösten Zustand

1969 ◽  
Vol 24 (5) ◽  
pp. 603-612 ◽  
Author(s):  
J.-H. Klemme

In cell free extracts of Rps. capsulata obtained by exposure of cells to ultrasonic oscillation, about 90% of the hydrogenase is associated with the particulate chromatophore fraction. The particulate enzyme reacts with methylene blue (MB), menadione, phenazonium methosulfate (PMS), dichlorophenolindophenol (DCPIP), cytochrome c, p-benzoquinone (BQ), ferricyanide and O2,, but does not react with benzylviologen (BV), pyridinnucleotides and flavinnucleotides. Treatment of chromatophores with sodiumlaurylsulfate inactivates the hydrogenase reaction with PMS, DCPIP, BQ and ferricyanide. The MB-linked or menadione-linked hydrogenase is not destroyed by the detergent. The hydrogenase reaction with BV is increased more than 20-fold after incubation of the chromatophores with the lipid-dispersing agent. Treatment of chromatophores with acetone and petroleum ether almost completely inactivates the hydrogenase reaction with PMS and BQ. The reaction rate of the DCPIP-linked and the ferricyanide-linked hydrogenase is somewhat decreased, whereas the MB-linked, the menadione-linked and the BV-linked hydrogenase reactions still exhibit about 100% of the original activity. By extraction of the acetone-treated chromatophores with glycine-NaOH-buffer (pH 9), about 10 — 15% of the particulate hydrogenase is solubilized. The enzyme was 9-fold purified by ammonium sulfate precipitation and chromatography on DEAE-cellulose. The purified enzyme contains no cytochrome. The relative reaction rates of the solubilized enzyme with different electron acceptors are similar to the corresponding reaction rates of the acetonetreated chromatophores. Extraction of chromatophores with n-butanol results in the solubilization of 5 — 10% of the particulate enzyme. By extraction of acetone-treated chromatophores with 0,5% Triton X-100, 40% of the particulate hydrogenase is solubilized. The fractionation of the extract with ammonium sulfate results in the isolation of a cytochrome c-containing particle which exhibits a 3-fold increased hydrogenase activity.

1977 ◽  
Vol 161 (2) ◽  
pp. 357-370 ◽  
Author(s):  
C W Bamforth ◽  
P J Large

1. Extracts of amine-grown Pseudomonas aminovorans contained a particle-bound N-methylglutamate dehydrogenase (EC 1.5.99.5). The enzyme was not present in succinate-grown cells, and activity appeared before growth began in succinate-grown cells which had been transferred to methylamine growth medium. 2. Membrane-containing preparations from methylamine-grown cells catalysed an N-methylglutamate-dependent uptake of O2 or reduction of cytochrome c, which was sensitive to inhibitors of the electron-transport chain. 3. N-Methylglutamate dehydrogenase activity with phenazine methosulphate or 2,6-dichlorophenol-indophenol as electron acceptor could be solubilized with 1% (w/v) Triton X-100. The solubilized enzyme was much less active with cytochrome c as electron acceptor and did not sediment in 1 h at 150000g. Solubilization was accompanied by a change in the pH optimum for activity. 4. The solubilized enzyme was partially purified by Sepharose 4B and hydroxyapatite chromatograpy to yield a preparation 22-fold increased in specific activity over the crude extract. 5. The partially-purified enzyme was active with sarcosine, N-methylalanine and N-methylaspartate as well as with N-methylglutamate. Evidence suggesting activity with N-methyl D-amino acids as well as with the L-forms was obtained. 6. The enzyme was inhibited by p-chloromercuribenzoate, iodoacetamide and by both ionic and non-ionic detergents. 2-Oxoglutarate and formaldehyde were also inhibitors. 7. Kinetic analysis confirmed previous workers' observations of a group transfer (Ping Pong) mechanism. 8. Spectral observations suggested that the partially purified preparation contained flavoprotein and a b-type cytochrome. 9. The role of the enzyme in the oxidation of methylamine is discussed.


1982 ◽  
Vol 37 (3-4) ◽  
pp. 193-198 ◽  
Author(s):  
Hendrik Hüdig ◽  
Gerhart Drews

Abstract A cytochrome oxidase (EC 1.9.3.1) was solubilized from the membrane fraction of aerobically grown cells of Rhodopseudomonas capsulata by treatment with Triton X-100. The enzyme was purified 160 fold by chromatography on DEAE-Sepharose CL-6B and affinity chromatography on cytochrome c-thiol activated Sepharose 4B.The purified enzyme has a pH-optimum at 8.5 and a temperature optimum at 35 °C. The ap­ parent Km for reduced horse cytochrome c is 24 μм (at pH 8 and 30 °C). The purified cytochrome oxidase was 50% inhibited by 1.5 μм KCN and 10 μм NaN3. The purified enzyme contained one polypeptide of mr 65,000 and 6-type cytochrome.


1980 ◽  
Vol 187 (2) ◽  
pp. 437-446 ◽  
Author(s):  
Lilian M. Y. Lee ◽  
Antonieta K. Salvatore ◽  
Peter R. Flanagan ◽  
Gordon G. Forstner

Maltase/glucoamylase from the rat intestinal brush-border membrane was solubilized by homogenization of the intestinal mucosa in buffer containing 0.5% Triton X-100. After removal of the detergent with butan-1-ol, the enzyme was purified by chromatography on Sepharose 4B and DEAE-cellulose. The final specific activity was 70.3 units/mg of protein in six preparations, comparing favourably with the specific activity of 65.0 units/mg of protein of a pure papain-solubilized maltase/glucoamylase previously isolated and characterized by us [Flanagan & Forstner (1978) Biochem. J.173, 553–563]. The two enzymes were compared. Both migrated as single bands with the same mobility on sodium dodecyl sulphate/polyacrylamide-gel electrophoresis, were eluted at the same volume from Sepharose 4B, and had the same sedimentation pattern in mannitol gradients. The amino acid composition was similar; content of total apolar residues differed by 1.0mol%. Antibodies prepared against either enzyme gave identical precipitin lines with each. Neither enzyme bound tritiated Triton X-100. The only difference noted was the tendency of the detergent-solubilized enzyme to aggregate on storage, whereas the papain-solubilized enzyme remained unchanged. Both enzymes had two N-termini, glycine and arginine. When the two enzymes were dissociated by boiling in sodium dodecyl sulphate, each exhibited the same five species on sodium dodecyl sulphate/polyacrylamide-gel electrophoresis. Single N-termini were found in the two smaller species, 1 (glycine) and 2 (arginine), whereas larger species (3–5) had both N-terminal amino acids. Both the Triton- and papain-solubilized enzymes appear to be oligomers of species 1 and 2, indicating that the native enzyme contains two subunit types. Aggregation in aqueous solutions does not depend on a proteolytically susceptible peptide fragment at the N-terminus of either subunit.


1979 ◽  
Vol 32 (2) ◽  
pp. 153 ◽  
Author(s):  
RN Murdoch ◽  
DJ Kay ◽  
WJ Capper

Alkaline phosphatase in uterine homogenates from day 7 pregnant mice was solubilized using 0�2 % (v/v) Triton X-100 and extracted with 20% (v/v) n-butanol. The procedure, which resulted in 182- fold purification, included ammonium sulfate precipitation, DEAE-cellulose anion exchange chromatography and Sephadex 0200 gel filtration.


1977 ◽  
Vol 55 (10) ◽  
pp. 1114-1117 ◽  
Author(s):  
Gerrit H. Bomhoff ◽  
Mary Spencer

Cytochrome c oxidase (EC 1.9.3.1) has been solubilized by use of the nonionic detergents Triton X-114 and Triton X-100, from pea cotyledon mitochondria. Optimum assay conditions were determined for the oxidation of ferrocytochrome c in air. The results indicate that the plant cytochrome c oxidase resembles mammalian preparations in its sensitivity towards ionic strength and pH of the assay buffer.


1979 ◽  
Vol 34 (9-10) ◽  
pp. 721-725 ◽  
Author(s):  
Heinz Großmann ◽  
Manfred Liefländer

Abstract Acetylcholinesterase was released from bovine erythrocytes by Triton X-100 treatment and pu­rified by twofold affinity chromatography. The detergentfree enzyme was obtained with a specific activity of 4130 U /mg (303 000-fold purification) and a 25% yield. Alternatively, the commercial available crude enzyme was purified. The latter preparation has an uniform molecular weight (Mr 175 000). The Triton-solubilized enzyme, however, can be resolved after removal of the detergent in eight multiple forms (Mr 175 000 and multiple values), in the presence of Triton there exists only one form (Mr 338 000). The amino acid composition of the two enzyme preparations differs significantly. No differences were observed with respect to other properties: SDS gel electrophore­sis revealed two protein bands (Mr 166 000 and 86 000) with both preparations. The enzyme is a glycoprotein with a pI value of 4.3 and contains strongly bound phosphatidylethanolamine. The N-terminal amino acid has been found to be Glu (or Gin).


1995 ◽  
Vol 42 (2) ◽  
pp. 269-274 ◽  
Author(s):  
U Lenart ◽  
J Haplova ◽  
P Magdolen ◽  
V Farkas ◽  
G Palamarczyk

The membrane-bound sterolglucoside synthase from the yeast Saccharomyces cerevisiae has been solubilized by nonionic detergent, Nonidet P-40, Triton X-100, and partially purified by DEAE-cellulose column chromatography and ammonium sulfate fractionation. SDS/PAGE of the purified fraction revealed the presence of two protein bands of molecular mass 66 kDa and 54 kDa. In an attempt to identify further the polypeptide chain of sterolglucoside synthase, the partially purified enzyme was treated with [di-125I]-5-[3-(p-azidosalicylamide)]allyl-UDPglucose, a photoactive analogue of UDP glucose, which is a substrate for this enzyme. Upon photolysis the 125I-labeled probe was shown to link covalently to the 66 kDa protein. The photoinsertion was competed out by the presence of unlabeled UDPglucose thus suggesting that this protein contains substrate binding site for UDPglucose. Since photoinsertion of the probe to protein of 66 kDa correlates with the molecular mass of the protein visualized upon enzyme purification we postulate that the 66 kDa protein is involved in sterolglucoside synthesis in yeast.


1989 ◽  
Vol 261 (1) ◽  
pp. 43-47 ◽  
Author(s):  
B Pereira ◽  
S Sivakami

Maltase activity (EC 3.2.1.20) was solubilized from rabbit kidney brush-border membrane by using 1.0% Triton X-100 and purified 230-fold with an overall recovery of 30%. The purification procedure makes use of heat precipitation, chromatography on DE-52 DEAE-cellulose and gel filtration on Sephacryl S-300. Rabbit kidney brush border exhibited glucoamylase activity with a maltase/glucoamylase ratio of 1.5:1 to 2.0:1. During purification the maltase and glucoamylase activities behaved identically. The Mr of the complex is 590,000, and it appears to be composed of eight identical subunits linked by disulphide bridges.


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