Polyamines distribution

Gambacorta, Polyamine distribution in eukaryotes occurrence of sym-nor-spermidine and sym-nor-spermine in arthropods,... 

Table 11.1 Polyamine distribution in Escherichia coli and rat liver...

Polyamine distribution Putrescine (mM) Spermidine (mM) Spermidine (mM) Spermine (mM)... 

Miyamoto S, Kashiwagi K, Ito K et al (1993) Estimation of polyamine distribution and polyamine stimulation of protein synthesis in Escherichia coli. Arch Biochem Biophys 300 63-68... 

Complexation of Cd with a series of polyamine macrocycles, but also related open-chain polyamines, comprising or attached to the 2,2 -bipyridine (bipy) and 1,10-phenanthroline (phen) moieties, has been studied by combined UV/vis spectrometry and potentiometry.24 Formation constants and distribution diagrams of the species present have been evaluated. As a result the thermodynamic stabilities, i.e., the formation constants, are lower for the bipy- and phen-contain-ing ligands than those for Cd complexes with aliphatic oligoaza macrocycles containing the same number of N donors. The probable reason is loss of flexibility of the ligands caused by the size and stiffness of the inserted heteroaromatic moieties. 

Novella-Rodriguez, S., Veciana-Nogues, M.T., Izquierdo-Pulido, M. and Vidal-Carou, M.C. (2003). Distribution of biogenic amines and polyamines in cheese, J. Food Sci., 68, 750. 

Ethambutol is a synthetic agent and not related to any of the other tuberculostatics. Its mechanism of action is not well understood but in actively dividing mycobacteria it appears to be an inhibitor of mycobacterial RNA synthesis. It also has effects on bacterial phosphate metabolism and on polyamine synthesis. It is an bacteriostatic agent and its main function in combination therapy is to delay the occurrence of resistance, mainly against isoniazid and rifampicin. It is well absorbed after oral administration. It is widely distributed, except to the CNS. Protein binding is about 20-30%. It is mainly excreted unchanged in the bile and urine with an elimination half-life of 3 h. Ethambutol is concentrated in erythrocytes and thus provides a depot for continuous release. 

S.2.3.3 Treatment of Trypanosomiasis The difluoromethylornithine (DFMO), eflomithine is a mechanism-based inhibitor of ornithine decarboxylase— a pyridoxal-dependent key enzyme of the polyamine s biosynthesis from ornithine. Fluorine atoms are essential for the inhibition process (cf. Chapter 7). Eflornithine was first clinically developed for cancer, but its development has been abandoned for this indication. The activity of eflornithine on trypanosomes was then discovered. Now, despite its very low bioavailability, eflornithine is the best therapy for sleeeping sickness (trypanosomiasis)—in particular, at the cerebral stage—due to Trypanosoma brucei gambiense parasite. Eflornithine is registered with orphan drug status and is distributed by the WHO. 

Our group described a simple access to well-defined hyperbranched polyamines from hyperbranched PEI with different molecular weights, narrow molecular weight distributions, and an adjustable degree of branching [91]. According to this protocol fully branched analogs of polypropyleneimine (PPI) and polyamidoa-mine (PAMAM) dendrimers can be derived from hyperbranched PEI (Mw = 5,000, and 25,000 g mol-1) in a two-step synthetic process (Scheme 2). 

Photocrosslinking 61-77 Photoinitiators 63 f., 69 Physical aging 132 Plasticity at the crack tip 135 Plastic zone 135 Poisson distribution 21 Polyaddition, irreversible step 18 Polyamines, addition to polyepoxides 25 f. Polycarboxylic acids 47 Polyepoxides and polyamines 25 f. Polyepoxy-polyamine systems, multicomponent 36... 

The already mentioned proteins OCTI and OCT3 transport small cationic substances, such as tetraalkyl ammonium compounds, polyamines such as spermine, monoamino-neurotransmitters, or N-methyl-nicotinamide across the basolateral plasma membrane [56]. OCTs play a key role in the distribution of cationic drugs and, therefore, drug interactions at the transporter level may become clinically relevant, as compounds with high affinity, such as prazosin or phenox-ybenzamine, may affect the excretion of other substrates. Certain liver diseases or obstructive cholestasis may result in alterations of hepatic clearance via these transporters. In rats, a 7-day bile duct ligation resulted in a marked downregulation of Octi and an increased hepatic accumulation of the Octi substrate tetraethylammonium [57]. 

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