Enzyme detoxifying

On pharmacodynamic grounds, tumor resistance may be caused by such diverse mechanisms as the mutation or redundancy of topo II, the overexpression and preferred nuclear localization of proteasome a-type subunits (leading to a anomalous degradation of topo II), genetic deletion or loss-of-function mutations of p53, overexpression of ROS-detoxifying enzymes, overexpression of Bcl-2 (leading to a diminished cyt c release), etc. However, none of these factors would universally predict the development of anthracycline-resistance in a given tumor or another. 

Organism Insecticide Detoxifying Enzyme Inhibitor (Synergist) Synergistic Ratio... 

In atherosclerosis and other heart diseases, the role of carotenoids as antioxidants is probable, but for these types of diseases and also for other degenerative diseases such as cancers, non-antioxidant activities constitute other possible prevention mechanisms. These activities are, for example, stimulation of gap junction communications between cells, and the induction of detoxifying enzymes. The... 

Schottel JL (1978) The mercuric and organomercurial detoxifying enzymes from a plasmid-bearing strain of Escherichia coli. J Biol Chem 253 4341-4349. 

Lu, W.H., Egerton, G.L., Bianco, A.E. and Williams, S.A. (1998) Thioredoxin peroxidase from Onchocerca volvulus a major hydrogen peroxide detoxifying enzyme in filarial parasites. Molecular and Biochemical Parasitology 91, 221-235. 

Nevertheless, the growing database for aquatic life indicates a number of generalizations (1) many PAHs are acutely toxic at concentrations between 50 and 1000 pg/L (2) deleterious sublethal responses are sometimes observed at concentrations in the range of 0.1 to 5.0 pg/L (3) uptake can be substantial, but depuration is usually rapid except in some species of invertebrates and (4) whole-body burdens in excess of 300 pg benzo[a]pyrene/kg (and presumably other PAHs) in certain teleosts would be accompanied by a rise in the activity of detoxifying enzymes. 

A factor of 3 was applied to the supporting studies as no specific susceptible populations were identified in monitoring studies or during the clinical use of nitroprusside solutions to control hypertension. The detoxifying enzyme rhodanese is present in all individuals including newborns. Application of the uncertainty factor to the El Ghawabi et al. (1975 as adjusted by the NRC) and Grabois (1954) data results in a value close to the 8-h 1 ppm concentration in the Leeser et al. (1990) study. 

No specific susceptible populations were identified during monitoring studies or during the clinical use of nitroprusside solutions to control hypertension. The detoxifying enzyme rhodanese is present in all individuals, including newborns. 

Yu SJ (1983) Induction of detoxifying enzymes by allelochemicals and host plants in the fall armyworm. Pestic Biochem Physiol 19 330-336 Yu SJ (1984) Interactions of allelochemicals with detoxification enzymes of insecticide-susceptible and resistant fall armyworms. Pestic Biochem Physiol 22 60-68 Yu SJ (1986) Consequences of induced foreign compound-metabolizing enzymes in insects. In Brattsten LB, Ahmad S (eds) Molecular aspects of insect-plant associations. Plenum, New York, pp 153-174... 

Mixed-function Oxidase Induction.-- Indirect evidence of environmental induction of detoxifying enzymes in the R fish has been observed as an increase in the acute toxicity of parathion and a simultaneous decrease in NADPH-dependent parathion... 

At the initial stages of a release, when the benzene-derived compounds are present at their highest concentrations, acute toxic effects are more common than they are later. These noncarcinogenic effects include subtle changes in detoxifying enzymes and liver damage. Generally, the relative aquatic acute toxicity of petroleum will be the result of the fractional toxicities of the different hydrocarbons present in the aqueous phase. Tests indicate that naphthalene-derived chemicals have a similar effect. 

Bowyer P et al (1995) Host range of a plant pathogenic fungus determined by a saponin detoxifying enzyme. Science 267 371... 

Laluente MT, Sala JM, Zacarias L (2004) Active oxygen detoxifying enzymes and phenylalanine ammonia-lyase in the ethylene-induced chilling tolerance in citrus fmit. J Agric Food Chem 52(11) 3606-3611... 

Pathogen Counterattack Fungal Detoxifying Enzymes and Paldoxins... 

Insects have developed resistance to cyanide, chlorinated hydrocarbons, organophosfiiates, carbamates, synthetic pyrethroids, and other insecticides ( ). This is not surprising vrtien considering the same complex of detoxifying enzymes, mainly r resented by hydrolytic, conjugative, and oxidative enzymes 9) is capable of detoxifying natural toxins as well as man-made materials. This ability is due to apprcpriate enzymes and/or isozymes that results in broad-substrate capabilities. For insects that feed on a wide variety of hosts (polyphagy), the spectrum of toxins that can be dealt with is truly remarkable. 

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