Sulphate conjugationSulphate conjugation

A sulphate molecule is transferred from the A sulphate molecule is transferred from the cofactor (3`-phosphoadenosine 5`-cofactor (3`-phosphoadenosine 5`-phosphosulphate, PAPS) to the substrate by phosphosulphate, PAPS) to the substrate by enzymes known as sulfotransferases.enzymes known as sulfotransferases.

Conjugation ReactionsConjugation Reactions Sulfation Sulfation

)3-`phosphoadenosine 5`-phosphosulphate( PAP

S)

Examples

ethanol p-hydroxyacetanilide 3-hydroxycoumarin

Sulfation may produce active Sulfation may produce active metabolitesmetabolites

Conjugation ReactionsConjugation ReactionsAcetylationAcetylation

The transfer of acetyl group takes place in The transfer of acetyl group takes place in presence of N-acetyl transferases.presence of N-acetyl transferases.

In acetylation although water solubility is not In acetylation although water solubility is not increased, it helps in terminating the increased, it helps in terminating the pharmacological activity of the drug or its pharmacological activity of the drug or its amino metabolite.amino metabolite.

Examples: Procainamide, isoniazid, sulfanilimide, histamine

NAT (N-Acetyl transferase)enzyme is found in many tissues, including liver .

Isoniazide

Amino acid conjugationAmino acid conjugation

Cinnamic acid

Glycine is the most common amino acid used Glycine is the most common amino acid used for conjugation, while a fewfor conjugation, while a few glutamine glutamine conjugates have been identified in humans.conjugates have been identified in humans.