To estimate the polyamine distribution in bovine lymphocytes and rat liver, the binding constants (K) for DNA, RNA, phospholipid, and ATP were determined under the conditions of 10 mM Tris-HCl, pH 7.5, 2 mM Mg2+, and 150 mM K+. The binding constants of spermine for calf thymus DNA, Escherichia coli 16 S rRNA, phospholipid in rat liver microsomes and ATP were 1.15 x 10(2), 6.69 x 10(2), 2.22 x 1...

Steady-state free Ca2+ concentrations have been measured with a Ca2+ electrode using suspensions of isolated rat liver mitochondria or saponin-treated hepatocytes. Mitochondria, when incubated in the presence of Mg2+ and MgATP2-, maintain a steady-state PCB2+ (-log [Ca2+]) of approximately 6.1 (0.8 FM). Addition of spermine lowered this value to a pCa2+ of 6.6 (0.25 pM). Spermine was the most...

We have previously showed that platinum drugs up-regulate SSAT and SMO and down-regulate ODC and SAMDC in the polyamine pathway. Several studies including our own established that platinum drugs combined with polyamine analog DENSPM produces synergistic increase in SSAT activity with polyamine depletion. Since polyamine pathway is an important therapeutic target, we investigated whether agents ...

Spermine was toxic to BHK-21/C13 cells in the absence of any extracellular metabolism of the amine. Inhibition of copper-containing amine oxidases with aminoguanidine partially prevented the response, whereas inhibition of polyamine oxidase with MDL-72,527 exacerbated the effect. Oxidation by an intracellular copper-containing amine oxidase may be involved in the toxicity of spermine, whereas t...

It has been previously described that elevation of endogenous spermine levels in Arabidopsis could be achieved by transgenic overexpression of S-Adenosylmethionine decarboxylase (SAMDC) or Spermine synthase (SPMS). In both cases, spermine accumulation had an impact on the plant transcriptome, with up-regulation of a set of genes enriched in functional categories involved in defense-related proc...

P-glycoprotein, encoded by the multidrug resistance gene MDR1, is an ATP-driven drug efflux pump which is highly expressed at the blood-brain barrier of vertebrates. Drug efflux of macrocyclic lactones by P-glycoprotein is highly relevant for the therapeutic safety of macrocyclic lactones, as thereby GABA-gated chloride channels, which are confined to the central nervous system in vertebrates, ...

Reaction between 4-aminopyridine and a dinuclear zinc(II) component of a Robson macrocyclic ligand has resulted in the formation of a molecular ladder element motif. X-ray single crystal structural analysis indicates that two pyridine rings are assembled at the same direction of the macrocycle, which are placed in a nearly parallel way via pi-pi interactions, forming a concavity structure with ...

The influence of spermine on the potassium loss from yeast cells as a consequence of membrane-disturbing actions was investigated. Spermine interfered strongly in the action membrane-active bactericides on yeast cells; this interference resembles the action of certain metal ions. Spermine provides a protection against the positively charged parasosaniline and accomplishes a strong potentiation ...