Endogenous compounds conjugation reactions

Phase 2 reactions make drugs or Phase 1 metabolites into more hydrophilic, less toxic substances by conjugation with endogenous compounds in the liver. 

Phase II reactions are also known as conjugation reactions because they involve the joining together of a substrate compound with another species that occurs normally in (is endogenous to) the organism.5 This can occur with unmodified xenobiotic compounds, xenobiotic compounds that... 

Possible obstacles to using immunoassays are created by environmental factors, such as pH, temperature, or other food product ingredients, e.g., endogenous enzymes whose specificity is similar to the specificity of the enzyme present in the conjugate, colorings present in a given samples can interfere with the color obtained from the enzyme-substrate reaction, phenolic compounds which can adsorb proteins. 

Phase II This phase consists of conjugation reactions. If the metabolite from Phase I metabolism is sufficiently polar, it can be excreted by the kidneys. However, many metabolites are too lipophilic to be retained in the kidney tubules. A subsequent conjugation reaction with an endogenous substrate, such as glucuronic acid, sulfuric acid, acetic acid or an amino acid results in polar, usually more water-soluble compounds that are most often therapeutically inactive. Glucuronidation is the most common and the most important conjugation reaction. Neonates are deficient in... 

Conjugation reactions of xenobiotics or their metabolites with endogenous substrates produce highly hydrophilic metabolites however, to a lesser extent functional groups may be also methylated or acetylated to produce less hydrophilic compounds. 

Phase II drug biotransformation involves reaction (conjugation) of a range of functional groups with endogenous compounds (Table 1). The resultant... 

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