Chemical agents enzymes

Temperature Ionic strength Solvents Electromagnetic radiation (UV, light) Electric fields Mechanical stress, strain Sonic radiation Magnetic fields pH Specific ions Chemical agents Enzyme substrates Affinity ligands Other biochemical agents... 

A skinned fiber is a muscle fiber, the sarcolemma of which has been mechanically removed or which is made freely permeable to small molecules, such as Ca2+, Mg2+, EGTA, ATP, soluble enzymes and others by a chemical agent (saponin, (3-escin or Staphylococcus a-toxin). The organization of the sarcoplasmic reticulum (SR) and myofibrils is kqrt as they are in the living muscle. 

Nerve agents Highly toxic and potentially lethal chemical agents that affect the human nervous system by inhibiting the enzyme that aids the transmission of nerve impulses. Causes blurred vision, weeping, nausea, vomiting, urinary incontinence, respiratory distress, and reduced mental capability by attacking the nervous system. 

Whether a toxin is naturally reactive to biological macromolecules or receptors, or requires metabolic activation to produce such a species, e.g. the enzyme-mediated transformation of tremorine (9) to the active parasympathomimetic agent oxotremorine (10), it will usually be subject to chemical or enzymic inactivation in vivo. Interruption of the latter process via appropriate substitution may thus lead to an increase in biological activity or toxicity over that of the parent compound. Perhaps the most striking example of this is provided by the extreme metabolic stability and toxicity of TCDD and the nontoxicity of its de- chloro analogue dibenzodioxin (Table 3). 

There is no dearth of chemical compounds that will cause a rise in blood pressure when injected into the experimental animal. Extracts of plant and animal tissues yield several, and enzymes present in the tissues will often produce pressor substances as a result of autolysis. For a chemical agent then to be proved as a cause of hypertension it must be found as such in the animal and in greater amount in the hypertensive than in the normal animal. The substance must be capable of producing a continued elevation of blood pressure when administered continuously to the normal animal. The substance must be of such a nature that the body does not make corrective or adaptive responses to it. In this fashion tachyphylaxis or immunological reactions may reduce the action of certain agents if given repeatedly. 

W.E. Lee, H.G. Thompson, J.G. Hall and D.E. Bader, Rapid detection and identification of biological and chemical agents by immunoassay, gene probe assay and enzyme inhibition using a silicon-based biosensor, Biosens. Bioelectron., 14(10-11) (2000) 795-804. 

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