نتایج جستجو برای: polyamine
تعداد نتایج: 4366 فیلتر نتایج به سال:
Increased polyamine concentrations in the blood and urine of cancer patients reflect the enhanced levels of polyamine synthesis in cancer tissues arising from increased activity of enzymes responsible for polyamine synthesis. In addition to their de novo polyamine synthesis, cells can take up polyamines from extracellular sources, such as cancer tissues, food, and intestinal microbiota. Because...
N,N'-Bis(benzyl)polyamine analogs were found to be substrates for highly purified polyamine oxidase. Metabolism of these analogs was apparently dependent on molecular O2 and resulted in the formation of benzaldehyde, H2O2, and a polyamine analog with free terminal amines. The debenzylation reaction was optimal between pH 9 and 10, identical to the pH optimum for polyamine oxidase activity when ...
The purpose of this paper was to better understand the role of polyamine transport in pancreatic cancers.This paper identifies potential biomarkers for assessing the relative tumor commitment to polyamine biosynthesis or transport. Cell lines with low polyamine import activity and low ATP13A3 protein levels appear committed to polyamine biosynthesis and required high concentrations of the polya...
In plants, γ-aminobutyric acid (GABA) is synthesized by polyamine degradation pathway besides GABA shunt. Aminoguanidine (AG) is a specific inhibitor of the key enzyme (diamine oxidase, DAO) for GABA formation in polyamine degradation pathway. In this study, AG was applied to study the functions of polyamine degradation pathway on growth and GABA accumulation in germinating fava bean under hypo...
Interest in polyamine catabolism has increased since it has been directly associated with the cytotoxic response of multiple tumour types to exposure to specific anti-tumour polyamine analogues. Human polyamine catabolism was considered to be a two-step pathway regulated by the rate-limiting enzyme spermidine/spermine N(1)-acetyltransferase (SSAT) that provides substrate for an acetylpolyamine ...
Human cells depleted of the naturally occurring polyamines putrescine, spermidine, and spermine exhibit altered chromatin structure and marked deficiencies in DNA replicative and repair processes. Similar effects have been observed following treatment of normal mammalian cells with various heavy metal salts. In an attempt to better understand how metals interfere with normal DNA metabolic proce...
Because intracellular polyamines have a critical role in cell proliferation and death pathways, the polyamine metabolic pathway represents a potential target for intervention in cancers. A number of polyamine analogues have been identified that downregulate polyamine synthesis and enhance polyamine catabolism, thereby depleting intracellular polyamines. Treatment of human breast cancer cell lin...
The natural polyamines are ubiquitous multifunctional organic cations which play important roles in regulating cellular proliferation and survival. Here we present a novel approach to investigating polyamine functions by using optical isomers of MeSpd (alpha-methylspermidine) and Me2Spm (alpha,omega-bismethylspermine), metabolically stable functional mimetics of natural polyamines. We studied t...
Senescence is an integral part of the normal developmental cycle of plants and can be traced in cell, tissue and organ level. This work was focused on the efficiency of post-harvest treatment with the free polyamine spermine (Spm) to extend the vase life of cut rose flowers as an anti-senescence compound. Spm treatment was applied at the rates of 0, 1, 2 and 4 mM. Some morphological, biochemica...
We have compared the effects of treatment with each of three bis(ethyl)polyamine analogues on a human small cell lung carcinoma (SCLC) line, NCI H82, and a non-small cell line, NCI H157, an undifferentiated large cell lung carcinoma. The bis(ethyl)polyamines have been shown to interfere with polyamine metabolism, presumably by regulation of the polyamine biosynthetic pathway in a manner similar...
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