The majority of biotransformation takes place within the liver in cells called hepatocytes. However, several of the enzymes for phase I, phase II, and phase III reactions can also occur in extrahepatic tissues, such as adipose, intestine, kidney, lung, and skin.

What is involved in biotransformation?

Biotransformation means chemical alteration of chemicals such as nutrients, amino acids, toxins, and drugs in the body. It is also needed to render non-polar compounds polar so that they are not reabsorbed in renal tubules and are excreted.

What is biotransformation in biology?

Biotransformation, sometimes referred to as metabolism, is the structural modification of a chemical by enzymes in the body. Chemicals are biotransformed in several organs, including the liver, kidneys, lungs, skin, intestines, and placenta, with the liver being the most important.

What causes biotransformation?

Biotransformation refers to the process by which lipophilic (fat-soluble), xenobiotic (foreign), or endobiotic (endogenous) chemicals are converted in the body by enzymatic reactions to products that are more hydrophilic (water-soluble).

Where does Phase 2 metabolism occur?

Glucuronidation, the most common phase II reaction, is the only one that occurs in the liver microsomal enzyme system. Glucuronides are secreted in bile and eliminated in urine. Thus, conjugation makes most drugs more soluble and easily excreted by the kidneys.

Biotransformation

Where does Phase 1 and Phase 2 metabolism occur?

The majority of biotransformation takes place within the liver in cells called hepatocytes. However, several of the enzymes for phase I, phase II, and phase III reactions can also occur in extrahepatic tissues, such as adipose, intestine, kidney, lung, and skin.

Where does Phase 1 xenobiotic metabolism occur?

Although Phase I drug metabolism occurs in most tissues, the primary and first pass site of metabolism occurs during hepatic circulation. Additional metabolism occurs in gastrointestinal epithelial, renal, skin, and lung tissues.

What is biotransformation of hydrocarbon?

Biotransformation is a process by which organic compounds are transformed from one form to another to reduce the persistence and toxicity of the chemical compounds.

Where does amino acid conjugation occur?

In relation to xenobiotic carboxylic acids, amino acid conjugation involves enzymes located principally in the mitochondria of liver and kidney while conjugation of bile acids is extramitochondrial, involving enzymes located in the endoplasmic reticulum and peroxisomes (Reilly et al., 2007, Knights et al., 2007).

What are metabolites made of?

Primary metabolites are synthesized by the cell because they are indispensable for their growth. Significant representatives are amino acids, alcohols, vitamins (B2 and B12), polyols, organic acids, as well as nucleotides (e.g. inosine-5'-monophosphate and guanosine-5'-monophosphate).

What is biotransformation in plant tissue culture?

Biotransformation is the process whereby a substance is changed from one chemical to another (transformed) by a chemical reaction within the body”.

How many phases happen during biotransformation?

It appears that the metabolism of most foreign compounds occurs in two phases.

Where does drug metabolism occur on a cellular level?

Most drugs must pass through the liver, which is the primary site for drug metabolism. Once in the liver, enzymes convert prodrugs to active metabolites or convert active drugs to inactive forms. The liver's primary mechanism for metabolizing drugs is via a specific group of cytochrome P-450 enzymes.

What is a pharmacodynamic drug?

Abstract. Pharmacodynamic drug-drug interactions (DDIs) occur when the pharmacological effect of one drug is altered by that of another drug in a combination regimen. DDIs often are classified as synergistic, additive, or antagonistic in nature, albeit these terms are frequently misused.

How does biotransformation help the environment?

Biotransformation can be used as a cleanup method for both contaminated soil and water. ... In situ technologies do not require excavation of the contaminated soils and so may be less expensive, create less dust, and cause less release of contaminants than ex situ techniques.

Where are non microsomal enzymes present?

Explanation: Non-microsomal enzymes include those that are present in soluble form in the cytoplasm and those attached to the mitochondria but not to the endoplasmic reticulum.

What enzyme causes conjugation?

Conjugation reactions are catalyzed by enzymes known as transferases.

What is conjugation in the liver?

Conjugation. Glucuronidation, the most common phase II reaction, is the only one that occurs in the liver microsomal enzyme system. Glucuronides are secreted in bile and eliminated in urine. Thus, conjugation makes most drugs more soluble and easily excreted by the kidneys.

Where is glucuronic acid found?

Glucuronic acid (C₆H₁₀O₇), a derivative of glucose, is produced in the liver of humans and most animals. It is a highly soluble compound that can bind to substances such as hormones, drugs, and toxins to facilitate their transport around the body.

What is biotransformation in the environment?

Biotransformation is the chemical modification (or modifications) made by an organism on a chemical compound, often associated with change (increase, decrease, or little change) in pharmacologic and toxicologic activity.

What is biotransformation of a drug?

Biotransformation is a process by which organic compounds are transformed from one form to another, aided by organisms such as bacteria, fungi and enzymes. It plays a major role and determines the fate of the prospective drugs.

What is enzyme biotransformation?

Biotransformation is the process through which the functional groups of organic compounds are modified by living cells to a chemically different product. ... Biotransformation enzymes help to produce “nature-like” biodegradable compounds, and are gaining importance in this aspect.

What is biotransformation in toxicology?

Biotransformation is the metabolic conversion of endogenous and xenobiotic chemicals to more water-soluble compounds. ... Chemical modification of a xenobiotic by biotransformation may alter its biological effects. Some drugs undergo biotransformation to active metabolites that exert their pharmacodynamic or toxic effect.

What is the Phase 1 and Phase 2 of hepatic drug metabolism?

Phase I reactions of drug metabolism involve oxidation, reduction, or hydrolysis of the parent drug, resulting in its conversion to a more polar molecule. Phase II reactions involve conjugation by coupling the drug or its metabolites to another molecule, such as glucuronidation, acylation, sulfate, or glicine.