Biodegradation of high molecular weight lignin under sulfate reducing conditions: Lignin degradability and degradation by-products

SummaryThe present study is concerned with the formation of fibrin-fibrinogen associations in the presence of FXIIIa while fibrinolysis was inhibited by aprotinin and EACA. SDS agarose-poly acryl-amide gel electrophoresis on 2.5% gels under non-reducing conditions and ultracentrifugation of the associations on urea-sucrose density gradients showed the formation of soluble crosslinked high molecular weight (HMW) fibrin-fibrinogen polymers with an estimated molecular size up to 10 times that of fibrinogen. After incubation of a mixture of 131I-fibrinogen (4 mg/ml) and 125I-desAA-fibrin (0.2 mg/ml) with FXIIIa (2 U/ml) for 1 h at 37ΰ C, about 5% of the fibrinogen and 80% of the fibrin was incorporated into the generated soluble HMW polymers. The detection of soluble crosslinked fibrin-fibrinogen polymers could be a useful diagnostic criterion for imminent DIC.

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Isolation and characterization of a high molecular weight cytochrome from the sulfate reducing bacteriumDesulfovibrio gigas

FEBS Letters ◽

10.1016/0014-5793(94)00563-x ◽

1994 ◽

Vol 347 (2-3) ◽

pp. 295-299 ◽

Cited By ~ 17

Author(s):

Liang Chen ◽

Manuela M. Pereira ◽

Miguel Teixeira ◽

António V. Xavier ◽

Jean Le Gall

Keyword(s):

Molecular Weight ◽

High Molecular Weight ◽

Sulfate Reducing ◽

Isolation And Characterization

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On the sensitivity of metallothioneins to oxidation during isolation

Biochemical Journal ◽

10.1042/bj1910475 ◽

1980 ◽

Vol 191 (2) ◽

pp. 475-485 ◽

Cited By ~ 113

Author(s):

D T Minkel ◽

K Poulsen ◽

S Wielgus ◽

C F Shaw ◽

D H Petering

Keyword(s):

Molecular Weight ◽

High Molecular Weight ◽

Rat Liver ◽

Chemical Reduction ◽

Cadmium Content ◽

Reducing Conditions ◽

Low Concentrations ◽

Disulphide Bond Formation ◽

Saturation Effects ◽

Molecular Weight Fractions

It is demonstrated that the distribution of metals among the Sephadex G-75 fractions of rat liver and horse kidney supernatant is altered by exposure to oxidizing conditions. In particular, the metals bound to metallothionein are displaced into high-molecular-weight fractions and, to a lesser extent, into the low-molecular-weight forms, under aerobic conditions. In this process, metallothionein zinc is much more labile than cadmium. An appreciable proportion of the thionein is also found in the high-molecular-weight fractions and can be recovered along with the metals by treatment with mercaptoethanol. This result shows that the distributions obtained aerobically with large cadmium content in the high-molecular-weight fractions are an artefact due to metallothionein oxidation and suggests that ‘spillage’ of metals such as cadmium may be due in large part to oxidative processes rather than saturation effects. Evidence is presented that disulphide-bond formation occurs as thionein becomes bound in the high-molecular-weight region and that chemical reduction is necessary to restore its normal elution behaviour. Mercaptoethanol added to the homogenates maintains the reducing conditions normally found in the cellular milieu and prevents the oxidation of the metallothionein redistribution of the metals during isolation. Under these conditions the rat liver metallothionein isolated from animals exposed to chronic low concentrations of cadmium in drinking water contains appreciable quantities of copper as well as zinc and contains much of the zinc that is present in horse kidney supernatants. Metallothionein can also be extracted from a 40 000g pellet after sonication of the pellet. Thus careful analytical studies of the sites of cadmium deposition in rat liver indicate that greater than 95% is bound to metallothionein.

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The autoactivation of rabbit hageman factor

Journal of Experimental Medicine ◽

10.1084/jem.150.5.1122 ◽

1979 ◽

Vol 150 (5) ◽

pp. 1122-1133 ◽

Cited By ~ 66

Author(s):

RC Wiggins ◽

CC Cochrane

Keyword(s):

Molecular Weight ◽

High Molecular Weight ◽

Clotting Factor ◽

Dependent Manner ◽

High Molecular Weight Kininogen ◽

Single Chain ◽

Hageman Factor ◽

Reducing Conditions ◽

Factor Α

Proteolytic cleavage and activation of isolated, single chain, zymogen Hageman factor was observed in the presence of kaolin alone. The rate of cleavage of kaolin-bound Hageman factor was enhanced 50-fold by the presence of prekallikrein and high molecular weight kininogen. The two-chain 82,000 dalton form of activated Hageman factor (α-HF(a)) also cleaved kaolin- bound single-chain Hageman factor in a dose-dependent manner, yielding fragments of 28,000 and, 50,000 dahons under reducing conditions. Cleavage of kaolin-bound single-chain Hageman factor was not inhibited by preincubation with diisopropylfluorophosphate (12 mM) for 10 min, but long-term incubation of Hageman factor with diisopropylfluorophosphate (up to 48 h) resulted in inhibition of cleavage of kaolin-bound Hageman factor to an extent proportional to the inhibition of procoagulant Hageman factor activity. Hageman factor cleavage was maximal when the kaolin concentration was {approximately} 10-fold greater than the Hageman factor concentration (wt:wt), and was partially inhibited by high molecular weight kininogen. Kaolin-bound Hageman factor cleaved clotting factor XI in an amount which correlated with the extent of cleavage of the Hageman factor. These findings are compatible with the concept that single-chain Hageman factor and α- HF(a), are both capable of cleaving and activating kaolin-bound Hageman factor and that a close molecular association of kaolin-bound Hageman factor molecules is required for this reaction.

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Modification of Synaptic Plasma Membrane Ca 2+ -ATPase in Ischemic Injury in an Animal Model of Global Ischemia

Stroke ◽

10.1161/str.32.suppl_1.354-a ◽

2001 ◽

Vol 32 (suppl_1) ◽

pp. 354-354

Author(s):

Asma Zaidi ◽

Angela M Cross ◽

Jennifer L Bean ◽

Mary L Michaelis

Keyword(s):

Molecular Weight ◽

Animal Model ◽

Plasma Membrane ◽

High Molecular Weight ◽

Critical Role ◽

Ischemic Injury ◽

Global Ischemia ◽

Synaptic Membranes ◽

Synaptic Plasma Membrane ◽

Reducing Conditions

P83 Regulation of [Ca 2+ ] i is altered in neurons during ischemic injury in stroke, but the precise mechanism(s) underlying the Ca 2+ dysregulation are not known. The plasma membrane Ca 2+ -ATPase (PMCA) is one of the two main Ca 2+ extrusion systems that play a critical role in maintaining neuronal Ca 2+ homeostasis. We have substantial evidence showing that this enzyme is very sensitive to oxidative stress. When exposed to very low concentrations of physiologically relevant oxidants, the PMCA has been shown to form high molecular weight aggregates and this is accompanied by the decline in its enzymatic activity. Because stroke-induced hypoxia is associated with the overproduction of reactive oxygen species (ROS) and a loss of Ca 2+ homeostasis, we carried out studies to determine if the PMCA is modified in an in vivo animal model of stroke. Global ischemia was induced in Sprague Dawley rats by occlusion of the common carotid arteries for defined time periods. The V max of PMCA activity in brain homogenates as well as in purified synaptic plasma membranes was significantly reduced following occlusion of the vessels, and the reduction was proportional to the time of ischemia. The loss in PMCA activity could not be reversed by addition of exogenous ATP, suggesting an alteration in the protein itself. Immunoblots of the synaptic membranes run under non-reducing conditions showed crosslinking of PMCA molecules to form high molecular weight adducts, and this too increased with increasing periods of ischemia. The PMCA aggregates were partially reversed under reducing conditions, indicating the involvement of sulphydryl group oxidation. These observations support the hypothesis that increased formation of ROS under ischemic conditions can oxidatively modify specific proteins critical for the regulation of free [Ca 2+ ] i levels. Such oxidative damage is likely to contribute to the loss of neuronal Ca 2+ regulation and neuronal viability in stroke. (Supported by AHA 9960343Z, AG 12993, and the Higuchi Biosciences Center, University of Kansas)

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Purification of high-molecular-weight follicle-stimulating hormone binding inhibitor in porcine follicular fluids

Acta Endocrinologica ◽

10.1530/eje.0.1300625 ◽

1994 ◽

Vol 130 (6) ◽

pp. 625-633 ◽

Cited By ~ 2

Author(s):

Kenichi Furukawa ◽

Mareo Yamoto ◽

Nobuyoshi Kokawa ◽

Ryosuke Nakano

Keyword(s):

Molecular Weight ◽

High Molecular Weight ◽

Polyacrylamide Gel Electrophoresis ◽

Follicle Stimulating Hormone ◽

Sodium Dodecyl ◽

Hormone Binding ◽

Reducing Conditions ◽

Sds Page ◽

Follicular Fluids ◽

Stimulating Hormone

Furukawa K, Yamoto M, Kokawa N, Nakano, R. Purification of high-molecular-weight folliclestimulating hormone binding inhibitor in porcine follicular fluids. Eur J Endocrinol 1994;130:625–33. ISSN 0804–4643 We performed the purification of high-molecular-weight follicle-stimulating hormone binding inhibitor (FSHBI) from porcine follicular fluids. The FSHBI activities of high-molecular-weight fractions acquired by ultrafiltration of follicular fluids from small, medium and large follicles with Centriflo CF25 membrane cone were 277.2 ± 24.6, 176.7 ± 3.0 and 141.3 ± 3.6U, respectively. By affinity chromatography of CF25 retentate with a column of Blue Sepharose CL6B, 94.1 ± 5.3% of FSHBI activity was recovered in the unretained fraction. The FSHBI in the unretained fraction was purified by anion-exchange chromatography with a column of Mono Q and gel filtration on Sephacryl S300HR. As a result of sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) of the final purified fraction, a single silver-stained band was observed at 310 kD under the non-reducing conditions. On the other hand, under the reducing conditions, SDS-PAGE revealed three bands at 178, 101 and 55kD. A double reciprocal plot analysis of this substance showed competitive inhibition in FSH binding. The results of the present study suggest the existence of a 310 kD FSHBI composed of three subunits of 178, 101 and 55 kD in porcine follicular fluids. K Furukawa, Department of Obstetrics and Gynecology, Wakayama Medical College, Shichibancho 27, Wakayama 640, Japan

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A preliminary study by gel filtration and ultracentrifugation of the interaction of bovine milk caseins with detergents

Journal of Dairy Research ◽

10.1017/s0022029900019191 ◽

1968 ◽

Vol 35 (3) ◽

pp. 439-446 ◽

Cited By ~ 31

Author(s):

G. C. Cheeseman

Keyword(s):

Molecular Weight ◽

High Molecular Weight ◽

Sodium Dodecyl ◽

Bovine Milk ◽

Gel Filtration ◽

Sedimentation Velocity ◽

Disulphide Bonds ◽

Reducing Conditions ◽

Preliminary Study ◽

The Individual

SummaryThe detergents sodium dodecyl sulphate and octyl phenoxy polyethoxyethanol interact with casein and cause dissociation of the high-molecular-weight casein aggregates. It is presumed that the detergent binds with hydrophobic regions in the casein molecule. The size of the complexes formed between detergents and αs1-casein, β-casein and κ-casein, as estimated by gel filtration and sedimentation velocity experiments, suggests that the caseins were complexed as monomers.During gel filtration under non-reducing conditions, detergent-κ-casein complexes were separated from other major components because of their conversion through formation of disulphide bonds into high-molecular-weight aggregates. This reaction, which did not occur in sedimentation velocity experiments, was presumably facilitated by the changes in the equilibrium between the individual caseins during gel filtration.Sedimentation velocity experiments showed that a ratio of about 40 detergent molecules to 1 casein molecule was required to give the smallest casein-detergent complex.

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