Biogenic amines structure

Catecholamines are biogenic amines with a catechol (o-dihydroxy-benzol) structure. They are synthesized in nerve endings from tyrosine and include dopamine, noradrenaline (norepinephrine) and adrenaline (epinephrine). 

Reuptake transporters are structures within the cell membranes of the presynaptic nerve terminal that serve to transport biogenic amines released from vesicles back into the nerve cell. These structures are targets for antidepressants, which block the transporter, thus increasing the bioavailability of neurotransmitters at postsynaptic receptors. 

Histamine is a mediator of several physiological and pathological processes within and outside the nervous system 249 The chemical structure of histamine has similarities to the structure of other biogenic amines, but important differences also exist 250... 

The chemical structure of histamine has similarities to the structures of other biogenic amines, but important differences also exist. Chemically, histamine is 2-(4-imidazolyl)ethylamine (Fig. 14-1). The ethylamine backbone is a common feature of many of the amine transmitters (e.g. dopamine, norepinephrine and serotonin). However, the imidazole nucleus, absent from other known transmitters, endows histamine with several distinct chemical properties. Among these is prototypic tautomerism, a property that permits it to exist in two different chemical forms (Fig. 14-1). The tautomeric properties of histamine are thought to be critical in the... 

Rudnick, G. (1997) Mechanisms of biogenic amine neurotransporters, in Neurotransmitter Transporters Structure, Function, and Regulation 1st ed. (Reith, M. E. A., ed.), Humana Press, Totowa, NJ, pp. 73-100. 

The biogenic amines are the preferred substrates of MAO. The enzyme comes in two flavors, MAO-A and MAO-B, both of which, like FMO, rely on the redox properties of FAD for their oxidative machinery. The two isoforms share a sequence homology of approximately 70% (81) and are found in the outer mitochondrial membrane, but they differ in substrate selectivity and tissue distribution. In mammalian tissues MAO-A is located primarily in the placenta, gut, and liver, while MAO-B is predominant in the brain, liver, and platelets. MAO-A is selective for serotonin and norepinephrine and is selectively inhibited by the mechanism-based inhibitor clorgyline (82). MAO-B is selective for /1-phcncthylaminc and tryptamine, and it is selectively inhibited by the mechanism-based inhibitors, deprenyl and pargyline (82) (Fig. 4.32). Recently, both MAO-A (83) and MAO-B (84) were structurally characterized by x-ray crystallography. 

Psilocybin (Figure 3.5a) and psilocin (Figure 3.5b) are indole derivatives substituted in position 4 by a hydroxyl group, where psilocybin is phosphory-lated. Due to its ionic properties, psilocybin is soluble in water. In addition, phosphorylation protects psilocybin from oxidative degradation. Both compounds are found to affect laboratory animals, but there is evidence that only the dephosphorylated form, psilocin, is the active species. In their structure the toxins resemble serotonine, a biogenic amine known to be a neurotransmitter. 

Abiotic model systems, 258t of bioactivity, 258-60 Absorption, distribution coefficients, 228 Absorption rate, equation, 228 Acephate, structure, 97 N-Acetylation, biogenic amines, 114 Actinomycete, anthelminthic activity, 5... 

Piperidine alkaloids contain the piperidine nucleus. The structural development of this group of alkaloids in synthesis is presented in Figure 52. Here a is L-lysine and /3 is cadaverine. The basic ring of j3 is the same as in a, although the activity of PLP reduces carbon dioxide. The j3 is biogenic amine, neither a stable nor a poisonous compound... 

Amine oxidases catalyze the oxidative deamination of both xenobiotic and biogenic amines, and thus have many critical biological functions. Two distinct classes differ in the nature of their prosthetic groups [1]. The flavin-(FAD flavin adenine dinucleotide)-dependent amine oxidases include monoamine oxidases (MAO A and B) and polyamine oxidases. Amine oxidases not containing FAD, the so-called semicarbazide-sensitive amine oxidases (SSAO), include both plasma amine oxidases and tissue amine oxidases. These contain quinonoid structures as redox cofactors that are derived from posttranslationally modified tyrosine or tryptophan side chains, topaoquinone frequently playing this role [2]. 

As a result of a high index of clinical suspicion and, on occasion, supporting biochemical data from other investigations, one of the first specialist investigations to ascertain whether a patient has an inborn error of biogenic amine metabolism is, as mentioned above, analysis of the CSF concentrations of HVA and 5HIAA. This is often performed in conjunction with the measurement of 3-methyldopa (3-MD), also known as 3-methoxytyrosine. 3-MD is formed from L-dopa via COMT activity and accumulates in conditions where aromatic amino acid decarboxylase activity is impaired. The chemical structures of HVA, 5HIAA and 3-MD are shown in Fig. 6.2.1. 

Mans, B.J. et al. (2007) The crystal structure of D7r4, a salivary biogenic amine-binding protein from the malaria mosquito anopheles gambiae. J. Biol. Chem., 282 (50), 36626-36633. 

All the MIP-QCM chemosensors for biogenic amines above described were quite selective with respect to functionally and structurally similar compounds (inset to Fig. 4). 

Epinephrine (see Figure 1) is synthesized in several steps from either phenylalanine or tyrosine (both amino acids). Two adjacent hydroxyl groups are placed on the aromatic ring, leading to the ring structure called catechol. These hydroxylations form the intermediate L-dopa, which in turn is converted to dopamine (a neurotransmitter), norepinephrine (also a neurotransmitter), and finally epinephrine. Epinephrine together with norepinephrine and dopamine make up the family of biogenic amines called catecholamines. 

Given the substantial difference in structure between cocaine and the biogenic amines it will be a challenge to see whether derivatives can be synthesized which could be used to prevent cocaine binding without blocking the transporter mechanism itself. 

G-protein coupled receptors respond to an astonishing variety of activators including short peptides, proteins, biogenic amines, nucleotides, lipids and even photons of light They are single subunit integral membrane proteins with a common seven-transmembrane domain structure in the form of a so-called helical wheel [Fig. 6-21(6)]. 

---