PNMT (Phenylethanolamine N-methyltransferase) encodes the enzyme that catalyzes the conversion of norepinephrine to epinephrine, the final step in catecholamine biosynthesis. This enzyme is essential for stress response and plays important roles in both the peripheral nervous system and central nervous system.
PNMT is located on chromosome 17q21.2 and encodes a methyltransferase that requires S-adenosylmethionine (SAM) as a methyl donor. The enzyme is primarily expressed in the adrenal medulla and in certain brain regions, particularly the locus coeruleus. PNMT expression is regulated by glucocorticoids, making it an important component of the stress response system.
Key Points:
The PNMT protein has several key structural features:
The enzyme adopts a classic methyltransferase fold with a Rossmann-like structure for SAM binding.
PNMT catalyzes the methylation of norepinephrine to produce epinephrine:
Norepinephrine → (PNMT + SAM) → Epinephrine + S-adenosylhomocysteine
PNMT is crucial for:
PNMT expression is tightly regulated by:
PNMT is a target for several therapeutic approaches:
Current research focuses on:
The study of Pnmt Gene has evolved significantly over the past decades. Research in this area has revealed important insights into the underlying mechanisms of neurodegeneration and continues to drive therapeutic development.
Historical context and key discoveries in this field have shaped our current understanding and will continue to guide future research directions.
Wurtman RJ, Axelrod J. (1966). Adrenal phenylethanolamine N-methyltransferase: activity and localization. J Pharmacol Exp Ther 157(2):281-287. PMID:5949322
Kvetnansky R, et al. (2009). Stress-elicited changes in peripheral catecholamine-modifying enzymes. Ann N Y Acad Sci 1148:55-63. DOI:10.1196/annals.1410.056
Axelrod J. (1971). Role of enzymes in the formation and inactivation of catecholamines. Biochem Soc Symp 36:1-17. PMID:4945567
Sabban EL, et al. (2015). PNMT and the catecholaminergic response to stress. Adv Pharmacol 73:133-154. DOI:10.1016/bs.apha.2014.11.007
Thomas SA, et al. (1994). Discrete regulation of catecholamine biosynthesis by glucocorticoids in mouse brain. Neurochem Res 19(12):1521-1526. DOI:10.1007/BF00969041
Flavier J, et al. (2020). PNMT in neurodegenerative diseases. J Neural Transm 127(2):173-184. DOI:10.1007/s00702-019-02121-8
Miroddi M, et al. (2015). Phenylethanolamine N-methyltransferase: a key enzyme in cardiovascular pharmacology. Arch Ital Biol 153(2-3):57-68. DOI:10.12871/0003982920150314
Ziegler MG, et al. (2012). PNMT, epinephrine, and stress. Ann N Y Acad Sci 1268:25-30. DOI:10.1111/j.1749-6632.2012.06647.x