Biologically important heterocycles Alice Skoumalov Name Formula Biologically
Biologically important heterocycles Alice Skoumalová
Name Formula Biologically important derivates Furanoses (sugars) Pyrrole Porphin (heme, vit. B 12 cobalamin) Bilirubin Proline, Hydroxyproline Indole Tryptophan, Serotonin, Melatonin LSD, Psilocybin Imidazole Histidine, Histamine Biotin (vit. H)
Name Formula Biologically important derivates Thiazole Thiamine (vit. B 1) Penicillin Pyranoses (sugars) Benzopyran (chroman) Tocopherol (vit. E) Pyridine Nicotinamide (vit. B 2) Pyridoxal (vit. B 6)
Name Formula Biologically important derivates Pyrimidine Nucleotide bases (U, T, C) Phenobarbital Vit. B 1 Purine Nucleotide bases (A, G) Hypoxanthine Caffeine Uric acid Pteridine Folic acid (vit. B 2) Isoalloxazine Riboflavin (vit. B 2)
Heme Ø complexed with protein in hemoglobin Ø 4 pyrrole rings coordinated with Fe 2+ Ø side chains: methyl, propionyl, vinyl Ø carries oxygen to the tissues Bilirubin Ø degradation product of heme (cleavage and reduction) Ø excreted in the bile Ø jaundice
Tryptophan Ø an amino acid (serotonin and melatonin precursor) Serotonin Ø a neurotransmitter (mood control) Ø many antidepressant drugs increase the level of serotonin in the brain Melatonin Ø a hormone (produced in response to the light-dark cycle → regulates circadian rhythms) Ø an antioxidant → protective effects
Histidine Ø an amino acid (histamine precursor) Histamine Ø a neurotransmitter (the major mediator of the allergic response → vasodilation, bronchoconstriction) Ø antihistamines (block histamine from binding to its receptor) Biotin (vit. H) Ø in liver, egg yolk, yeast products, legumes, nuts Ø function: carboxylation (the coenzyme of the carboxylases)
Thiamine (vit. B 1) Ø contains two heterocyclic rings Ø in grain, yeast products, pork Ø its deficiency (beri → neurological disturbances, cardiac insufficiency, and muscular atrophy) Ø function: oxidative decarboxylation Tocopherol (vit. E) Ø in cereals, liver, eggs, seed oil Ø function: antioxidant in membranes
Nicotinamide (niacin) Ø in meat, yeast products, fruit, vegetables Ø its deficiency (pellagra → skin damage, digestive disturbances, depression) Ø function: in the coenzymes NADH and NADPH (dehydrogenases) NAD+ NADH Pyridoxal (vit. B 6) Ø in meat, vegetables, grain products Ø function: the coenzyme in the amino acid metabolism
Nucleotide bases derived from pyrimidine Ø in nucleic acids Uracil (in RNA) Thymine (in DNA) Cytosine (in both RNA and DNA) Ø a nucleic acid base is N-glycosidically linked to ribose or 2 -deoxyribose Ø the sugar is esterified with phosphoric acid
Nucleotide bases derived from purine Ø in nucleic acids , ATP, NADP, FAD, Co. A Ø degradation of purine nucleotides → uric acid (excreted) Guanine Adenine (in both RNA and DNA) anhydride bonds (in both RNA and DNA) Uric acid an ester bond § the most important form of chemical energy in cells ATP
Folic acid Ø in fresh green vegetables, liver Ø its deficiency (megaloblastic anemia) Ø function: coenzyme in C 1 metabolism (nucleotide biosynthesis) Riboflavin Ø in milk, eggs Ø function: in the coenzymes FMN and FAD (oxidation and reduction) riboflavin FADH 2 FAD
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