Related Experiment Video
Updated: Jul 17, 2026
08:58
High-Throughput Measurement and Classification of Organic P in Environmental Samples
Published on: June 8, 2011
[Organophosphorus compounds: classification and enzyme reactions]
1Institut za medicinska istrazivanja i medicinu rada, Zagreb, Hrvatska. abosak@imi.hr
Arhiv Za Higijenu Rada I Toksikologiju
|February 3, 2007
Summary
Organophosphorus compounds, used as pesticides and nerve agents, can be toxic by inhibiting acetylcholinesterase. Their biological activity and toxicity depend on biotransformation reactions, which alter their effects on this critical enzyme.
Area of Science:
- Biochemistry
- Toxicology
- Organic Chemistry
Context:
- Organophosphorus compounds are widely used as pesticides, drugs, and nerve agents.
- Their toxicity is primarily linked to the inhibition of acetylcholinesterase, a key enzyme in neurotransmission.
- Some organophosphorus compounds require biotransformation to become biologically active and toxic.
Purpose:
- To classify organophosphorus compounds based on the groups attached to the central phosphorus atom.
- To describe the enzymes involved in the biotransformation of organophosphorus compounds.
- To illustrate the enzymatic reactions that modify the toxicity of these compounds.
Summary:
- Organophosphorus compounds are diverse derivatives of phosphoric, phosphonic, or phosphinic acids.
- Their acute toxicity stems from acetylcholinesterase inhibition, though sulfur-containing variants may require activation.
- Biotransformation pathways, involving various enzymes, critically determine the ultimate toxicity and biological activity of these compounds.
Impact:
- Provides a framework for understanding the chemical and biological properties of organophosphorus compounds.
- Highlights the crucial role of biotransformation in mediating organophosphorus toxicity.
- Informs the development of safer pesticides and therapeutic strategies by elucidating enzyme-mediated modifications.
Related Concept Videos
01:26Anticholinesterase Agents: Poisoning and Treatment
Anticholinesterases, also known as cholinesterase inhibitors, work by blocking the breakdown of acetylcholine, leading to its accumulation in the synaptic cleft. This accumulation indirectly enhances both muscarinic and nicotinic actions. These agents are classified as reversible or irreversible based on their mechanism of action.
Irreversible agents form a strong bond with the cholinesterase enzyme, making it inactive. The breakdown of the phosphorylated enzyme is slower than the...
Irreversible agents form a strong bond with the cholinesterase enzyme, making it inactive. The breakdown of the phosphorylated enzyme is slower than the...
01:29Indirect-Acting Cholinergic Agonists: Chemistry and Structure-Activity Relationship
Indirect-acting cholinergic agonists are agents that interact with the acetylcholinesterase enzyme in the synaptic cleft, preventing the breakdown of acetylcholine into choline and acetate. Consequently, the concentration of acetylcholine in the synaptic cleft increases. These agonists can be classified into reversible and irreversible inhibitors based on their duration of action.
Reversible inhibitors display short to medium durations of action. Short-acting agents include simple alcohols with...
Reversible inhibitors display short to medium durations of action. Short-acting agents include simple alcohols with...
01:22Indirect-Acting Cholinergic Agonists: Pharmacokinetics
Indirect-acting cholinergic agonists, or anticholinesterases, enhance the body's cholinergic activity by inhibiting acetylcholine's breakdown. They are categorized as reversible or irreversible agents based on their mechanism of action. They are further classified into short-acting, intermediate-acting, and long-acting agents based on their duration of action.
Reversible agents containing quaternary amines, such as neostigmine and edrophonium, are not easily absorbed orally because they are...
Reversible agents containing quaternary amines, such as neostigmine and edrophonium, are not easily absorbed orally because they are...
01:18Indirect-Acting Cholinergic Agonists: Mechanism of Action
Indirect-acting cholinergic agonists work by interacting with an enzyme called acetylcholinesterase (AChE) in the synaptic cleft. They can be reversible or irreversible inhibitors and have different effects on the enzyme.
Reversible inhibitors like edrophonium bind to a specific part of the enzyme called the anionic catalytic site. They form noncovalent bonds, which means they are not strongly attached to the enzyme. This creates a temporary and less stable enzyme–inhibitor complex, leading to...
Reversible inhibitors like edrophonium bind to a specific part of the enzyme called the anionic catalytic site. They form noncovalent bonds, which means they are not strongly attached to the enzyme. This creates a temporary and less stable enzyme–inhibitor complex, leading to...
01:28Microbial Bioremediation of Pesticides
Pesticides often feature structurally complex chemical architectures, incorporating halogen groups and multiple aromatic rings. These characteristics confer high chemical stability, rendering many pesticides resistant to natural degradation processes. This resistance poses significant environmental concerns, as persistent pesticide residues can accumulate in ecosystems and affect non-target organisms.Despite the inherent stability of many pesticides, certain microorganisms possess the metabolic...
01:22Direct-Acting Cholinergic Agonists: Chemistry and Structure-Activity Relationship
Cholinergic agonists or cholinomimetics mimic the action of acetylcholine to stimulate the parasympathetic nervous system. They are categorized into direct-acting and indirect-acting agents. The direct-acting cholinergic drugs induce the parasympathetic response by directly binding to the muscarinic or nicotine receptors. In comparison, the indirect-acting cholinergic drugs prevent acetylcholine hydrolysis, indirectly contributing to the extended parasympathetic response.
The direct-acting...
The direct-acting...