Target type: molecularfunction
Catalysis of the reaction: S-adenosyl-L-methionine(1+) + pyridine = N-methylpyridinium + S-adenosyl-L-homocysteine. [EC:2.1.1.87, RHEA:16893]
Pyridine N-methyltransferase activity refers to the enzymatic catalysis of the transfer of a methyl group from a donor molecule, typically S-adenosyl methionine (SAM), to a nitrogen atom within a pyridine ring. This process results in the formation of a N-methylated pyridine derivative. Pyridine N-methyltransferases play significant roles in various biological processes, including:
* **Neurotransmitter metabolism:** Pyridine N-methyltransferases are involved in the biosynthesis of neurotransmitters like nicotinamide adenine dinucleotide (NAD) and its derivatives. These molecules are essential for energy production, redox reactions, and signal transduction in the nervous system.
* **Drug metabolism:** Certain pyridine N-methyltransferases participate in the detoxification and metabolism of drugs, influencing their pharmacological effects and duration of action.
* **Plant metabolism:** Pyridine N-methyltransferases contribute to the biosynthesis of secondary metabolites in plants, including alkaloids and pigments. These compounds play a crucial role in plant defense against pathogens and herbivores.
* **Microbial metabolism:** Pyridine N-methyltransferases are involved in the metabolism of pyridine-containing compounds in bacteria and fungi, contributing to their growth and survival in diverse environments.
The catalytic mechanism of pyridine N-methyltransferases typically involves the following steps:
1. **Binding of SAM and the pyridine substrate:** The enzyme binds both the methyl donor (SAM) and the pyridine substrate.
2. **Methyl group transfer:** The methyl group from SAM is transferred to the nitrogen atom of the pyridine ring, forming a N-methylated pyridine derivative.
3. **Release of products:** The enzyme releases the N-methylated pyridine product and S-adenosyl homocysteine (SAH), a byproduct of the reaction.
The specific substrate specificity and reaction mechanism of pyridine N-methyltransferases can vary depending on the enzyme and its biological context.'
"
| Protein | Definition | Taxonomy |
|---|---|---|
| Nicotinamide N-methyltransferase | A nicotinamide N-methyltransferase that is encoded in the genome of human. [PRO:DNx, UniProtKB:P40261] | Homo sapiens (human) |
| Nicotinamide N-methyltransferase | A nicotinamide N-methyltransferase that is encoded in the genome of human. [PRO:DNx, UniProtKB:P40261] | Homo sapiens (human) |
| Compound | Definition | Classes | Roles |
|---|---|---|---|
| benzamide | benzamide : An aromatic amide that consists of benzene bearing a single carboxamido substituent. The parent of the class of benzamides. | benzamides | |
| 1,2,3,4-tetrahydroisoquinoline | 1,2,3,4-tetrahydroisoquinoline: RN given refers to cpd with locants as specified | isoquinolines | |
| quinoline | azaarene; mancude organic heterobicyclic parent; ortho-fused heteroarene; quinolines | ||
| isoquinoline | azaarene; isoquinolines; mancude organic heterobicyclic parent; ortho-fused heteroarene | ||
| 6-aminonicotinamide | 6-aminonicotinamide : A monocarboxylic acid amide resulting from the formal condensation of the carboxy group of 6-aminonicotinic acid with ammonia. An inhibitor of the NADP(+)-dependent enzyme, 6-phosphogluconate dehydrogenase, it interferes with glycolysis, resulting in ATP depletion and synergizes with DNA-crosslinking chemotherapy drugs, such as cisplatin, in killing cancer cells. 6-Aminonicotinamide: A vitamin antagonist which has teratogenic effects. | aminopyridine; monocarboxylic acid amide; primary amino compound | antimetabolite; EC 1.1.1.44 (NADP(+)-dependent decarboxylating phosphogluconate dehydrogenase) inhibitor; teratogenic agent |
| sinefungin | adenosines; non-proteinogenic alpha-amino acid | antifungal agent; antimicrobial agent | |
| n'-methyl-2-pyridone-5-carboxamide | N-methyl-6-pyridone-3-carboxamide : A pyridone that is 2-pyridone substituted with a carboxamide group at C-5 and a methyl group at N-1. N'-methyl-2-pyridone-5-carboxamide: structure | methylpyridines; pyridinecarboxamide; pyridone | metabolite; mouse metabolite |
| 4-Methoxybenzamide | benzamides | ||
| n(4)-adenosyl-n(4)-methyl-2,4-diaminobutanoic acid | |||
| s-adenosylhomocysteine | S-adenosyl-L-homocysteine : An organic sulfide that is the S-adenosyl derivative of L-homocysteine. S-Adenosylhomocysteine: 5'-S-(3-Amino-3-carboxypropyl)-5'-thioadenosine. Formed from S-adenosylmethionine after transmethylation reactions. | adenosines; amino acid zwitterion; homocysteine derivative; homocysteines; organic sulfide | cofactor; EC 2.1.1.72 [site-specific DNA-methyltransferase (adenine-specific)] inhibitor; EC 2.1.1.79 (cyclopropane-fatty-acyl-phospholipid synthase) inhibitor; epitope; fundamental metabolite |
| thionicotinamide | |||
| quinoline-3-carboxamide | quinoline-3-carboxamide: structure in first source |