Heterocyclic amine

Typically it is a nitrogen atom of an amine group that also makes the ring heterocyclic (e.g., pyridine), though compounds exist in which this is not the case (e.g., the drug zileuton).

Carcinogenic heterocyclic amines are created by high temperature cooking of meat and smoking of plant matter like tobacco.

Some well known heterocyclic amines are niacin (vitamin B3), nicotine (psychoactive alkaloid and recreational drug), and the nucleobases that encode genetic information in DNA.

The other two nucleobases, adenine and guanine, are also heterocyclic amines called purines; they are composed of a fused pyrimidine and imidazole.

[1] Heterocyclic amines are the carcinogenic chemicals formed from the cooking of muscle meats such as beef, lamb, pork, fish and poultry.

[1][2] HCAs form when amino acids and creatine (a chemical found in muscles) react at high cooking temperatures.

[5][6] While harmane has been found in roughly 50% higher concentrations in patients with essential tremor than in controls,[7] there is no direct correlation between blood-levels and levels of daily meat consumption, suggesting a difference in metabolism of this chemical plays a greater role.