Purification and Properties of an Amylopullulanase, a Glucoamylase, and an α-Glucosidase in the Amylolytic Enzyme System ofThermoanaerobacterium thermosaccharolyticum

1. The enzyme system from pig liver responsible for the αβ-elimination of l-serine O-sulphate was purified 1000-fold. 2. Isoelectric focusing produced two enzymically active fractions with isoelectric points at pH5.6 and 5.9 respectively. 3. Osmometry and gel filtration showed both enzymes to possess molecular weights of approx. 54000. 4. The separate activities exhibited similar amino acid compositions.

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Purification and properties of the methane mono-oxygenase enzyme system from Methylosinus trichosporium OB3b

Biochemical Journal ◽

10.1042/bj1610333 ◽

1977 ◽

Vol 161 (2) ◽

pp. 333-344 ◽

Cited By ~ 82

Author(s):

G M Tonge ◽

D E F Harrison ◽

I J Higgins

Keyword(s):

Cytochrome C ◽

Specific Activity ◽

Enzyme System ◽

Methylosinus Trichosporium ◽

Horse Heart Cytochrome ◽

Oxidation Of Methane ◽

Low Concentrations ◽

Purification And Properties ◽

Oxygenase Activity ◽

Highly Sensitive

1. A three-component enzyme system that catalyses the oxidation of methane to methanol has been highly purified from Methylosinus trichosporium. 2. The components are (i) a soluble CO-binding cytochrome c, (ii) a copper-containing protein and (iii) a small protein; the mol. wts. are 13 000, 47 000 and 9400 respectively. The cytochrome component cannot be replaced by similar cytochrome purified from Pseudomonas extorquens or by horse heart cytochrome c. 3. The stoicheiometry suggests a mono-oxygenase mechanism and the specific activity with methane as substrate is 6 micronmol/min per mg of protein. 4. Other substrates rapidly oxidized are ethane, n-propane, n-butane and CO. Dimethyl ether is not a substrate. 5. The purified enzyme system utilizes ascorbate or, in the presence of partially purified M. trichosporium methanol dehydrogenase, methanol as electron donor but not NADH or NADPH. 6. Activity is highly sensitive to low concentrations of a variety of chelating agents, cyanide, 2-mercaptoethanol and dithiothreitol. 7. Activity is highly pH-dependent (optimum 6.9-7.0) and no component of the enzyme is stable to freezing. 8. The soluble CO-binding cytochrome c shows oxidase acitivity and the relationship between this and the oxygenase activity is discussed.

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STUDIES ON THE PURIFICATION AND PROPERTIES OF THE SERINE-FORMING ENZYME SYSTEM

Journal of Biological Chemistry ◽

10.1016/s0021-9258(18)65303-7 ◽

1956 ◽

Vol 220 (2) ◽

pp. 775-785 ◽

Cited By ~ 8

Author(s):

Nicholas Alexander ◽

David M. Greenberg

Keyword(s):

Enzyme System ◽

Purification And Properties

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Electron Microscopic and Isozyme Study of a Case of Ochronosis

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100093699 ◽

1972 ◽

Vol 30 ◽

pp. 88-89

Author(s):

Jay W. Cha ◽

Perry J. Melnick

Keyword(s):

Benzene Ring ◽

Enzyme System ◽

Homogentisic Acid ◽

Degenerative Changes ◽

Acid Oxidase ◽

Electron Microscopic ◽

Tyrosine Metabolism ◽

Collagenous Tissues

Hereditary ochronosis in very few cases has been examined electron microscopically or histochemically. In this disease homogentisic acid, a normal intermediary of tyrosine metabolism, forms in excessive amounts. This is believed to be due to absence or defective activity of homogentisic acid oxidase, an enzyme system necessary to break the benzene ring and to further break it down to fumaric and acetoacetic acids. Ochronotic pigment, a polymerized form of homogentisic acid, deposits mainly in mesenchymal tissues. There has been a question whether the pigment originates from the collagenous tissues, or deposits passively, where in contrast to melanin it induces degenerative changes.

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