What is an example of a Phase II biotransformation?
What is an example of a Phase II biotransformation?
Examples of Phase II reactions: Glucouronidation. Sulfation. Acetylation.
What is hepatic biotransformation?
In addition to the liver, biotransformation processes occur in plasma, in the lungs, in the gastrointestinal tract and in the skin. Hepatic biotransformation increases the polarity of xenobiotics, thereby increasing their solubility in water and enhancing their biliary and renal excretion,.
Which enzyme is important in the phase 2?
Phase II drug metabolising enzymes are mainly transferases. This review covers the major phase II enzymes: UDP-glucuronosyltransferases, sulfotransferases, N-acetyltransferases, glutathione S-transferases and methyltransferases (mainly thiopurine S-methyl transferase and catechol O-methyl transferase).
What are the two phases of biotransformation?
Biotransformation of organic xenobiotics normally proceed in a first step of oxidation (phase I) that introduces a reactive group in the xenobiotic, and a second step of conjugation (phase II) with a nontoxic endogenous metabolite that yields an excretable product.
Which is Phase 2 biotransformation reaction?
Phase II reactions consist of adding hydrophilic groups to the original molecule, a toxic intermediate or a nontoxic metabolite formed in phase I, that requires further transformation to increase its polarity. These reactions include conjugation reactions, glucuronidation, acetylation, and sulfation.
What is the importance of biotransformation?
The major purpose of biotransformation is to chemically modify (metabolize) poorly excretable lipophilic compounds to more hydrophilic chemicals that are readily excreted in urine and/or bile. Without metabolism, lipophilic xenobiotics accumulate in biota, increasing the potential for toxicity.
What are the reactions in Phase 2 biotransformation?
Phase II biotransformation reactions include glucuronidation, sulfonation (more commonly called sulfation), acetylation, methylation, and conjugation with glutathione (mercapturic acid synthesis), which usually result in increased hydrophilicity and elimination.
What are the major elimination routes in biotransformation?
– Hydrophilic molecules are less able to cross cellular membranes, hence fluid filterable (kidneys). 2 – Major elimination routes are feces (biliary) and urine. – Biological half-life, T½ allows comparison of rates of removal. Biotransformation Reactions • Grouped as Phase I (functional group modification) and Phase II (conjugation). • Goals
How is xenobiotic biotransformation accomplished in Phase I?
Xenobiotic biotransformation is accomplished by a limited number of enzymes with broad substrate specificities. Phase I reactions involve hydrolysis, reduction, and oxidation. These reactions expose or introduce a functional group (—OH, —NH2, —SH, or —COOH), and usually result in only a small increase in hydrophilicity.
Which is an example of a biotransformation modification?
Biotransformation is the chemical modification (or modifications) made by an organism on a chemical compound. If this modification ends in mineral compounds like CO 2, NH 4+, or H 2 O, the biotransformation is called mineralisation .