Oxidase enzymes controlled

Chan-Palay V, Hochh M, Jentsch L, et al Raphe serotonin neurons in the human brain stem in normal controls and patients with senile dementia of the Alzheimer type and Parkinsons disease relationship to monoamine oxidase enzyme localization. Dementia 3 253-269, 1992... 

Poole1305 has reviewed the bacterial cytochrome oxidases, and has drawn attention to features which are not present in the mitochondrial enzyme, and which reflect the metabolic diversity and adaptability of bacteria. These are (1) the synthesis of the oxidases is controlled dramatically by the prevailing environmental conditions (2) some oxidases are multifunctional, and may use electron acceptors other than dioxygen (3) more than one type of oxidase may be present, each terminating a branched electron-transfer pathway. 

Polypyrrole Film Formation in Glucose Oxidase Enzyme Solution. Cyclic voltammograms recorded in the GOD and pyrrole solution showed an anodic peak current (E = 1.08 V), which suggested the polymerization of pyrrole in the above solution. However, the polymerization potential moved toward the more positive direction compared to the polymerization potential of PPy doped with Cl ( pa < 1.0 V). This is due to the fact that the polymerization is more difficult to take place in enzyme solution than in Cl solution because the enzyme solution is a much weaker electrolyte than NaCl it may also be due to the less conductive nature of the PPy-GOD film as compared to that of the PPy-Cl film. The polymerization current level was much lower in the enzyme solution than in the Cl solution because of the poor charge-transport property of the enzyme protein molecules. It was found that the constant current method was more suitable than the controlled potential method for making the PPy-GOD film on the GC electrode. 

Formaldehyde has three sources in the hinrian body (a) trader controlled conditions, as part of normal biological processes (endogenous formaldehyde cycle) (b) as a result of random processes (demethylase, peroxidase, semicaibazide-sensitive amino oxidase enzymes) (c) exogenously, from external sources (air, water, food, environmental pollution). Formaldehyde is by no means just a harmful byproduct in biological systems, it has essential functions, which are not yet known in sufficient depth. The question is not whether formaldehyde occurs in living organism. The question is its amount and the role it plays in the complex and dynamic cycle of methylation and demethylation. 

Figure 3 shows the response of the sensor to flowing buffer solution and citrated blood saturated with oxygen at 37°C. The percent response is defined as 100 [1-(I oxidase/I control)] where I oxidase is the current from the cell equipped with the enzyme matrix and I control the current from tlie cell with the enzyme-free matrix. 

In principle, combining EPR information with information from optical absorption spectroscopy ought to prove more definitive than does pure EPR. Unfortunately, absorption bands due to molybdenum in enzymes are weak and consequently have remained undetected beneath stronger absorb-tions from iron-sulfur, flavin, or heme centers. Therefore, the relatively recent finding that the heme-free molybdenum domain of the molecule may be isolated from sulfite oxidase by controlled proteolysis (Johnson and Rajag-opalan, 1977 see also Guiard and Lederer, 1977), is of very considerable interest One can only hope that it will prove possible, in due course, to collate the optical (Johnson and Rajagopalan, 1977) and EPR properties of such species. 

Hurst (19) discusses the similarity in action of the pyrethrins and of DDT as indicated by a dispersant action on the lipids of insect cuticle and internal tissue. He has developed an elaborate theory of contact insecticidal action but provides no experimental data. Hurst believes that the susceptibility to insecticides depends partially on the cuticular permeability, but more fundamentally on the effects on internal tissue receptors which control oxidative metabolism or oxidative enzyme systems. The access of pyrethrins to insects, for example, is facilitated by adsorption and storage in the lipophilic layers of the epicuticle. The epicuticle is to be regarded as a lipoprotein mosaic consisting of alternating patches of lipid and protein receptors which are sites of oxidase activity. Such a condition exists in both the hydrophilic type of cuticle found in larvae of Calliphora and Phormia and in the waxy cuticle of Tenebrio larvae. Hurst explains pyrethrinization as a preliminary narcosis or knockdown phase in which oxidase action is blocked by adsorption of the insecticide on the lipoprotein tissue components, followed by death when further dispersant action of the insecticide results in an irreversible increase in the phenoloxidase activity as a result of the displacement of protective lipids. This increase in phenoloxidase activity is accompanied by the accumulation of toxic quinoid metabolites in the blood and tissues—for example, O-quinones which would block substrate access to normal enzyme systems. The varying degrees of susceptibility shown by different insect species to an insecticide may be explainable not only in terms of differences in cuticle make-up but also as internal factors associated with the stability of oxidase systems. 

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