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Uptake of exogenous polyamines by the unicellular green alga Chlamydomonas reinhardtii and their effects on polyamine metabolism were investigated. Our data show that, in contrast to mammalian cells, Chlamydomonas reinhardtii does not contain short-living, high-affinity polyamine transporters whose cellular level is dependent on the polyamine concentration. However, exogenous polyamines affect polyamine metabolism in Chlamydomonas cells. Exogenous putrescine caused a slow increase of both putrescine and spermidine and, vice versa, exogenous spermidine also led to an increase of the intracellular levels of both spermidine and putrescine. No intracellular spermine was detected under any conditions. Exogenous spermine was taken up by the cells and caused a decrease in their putrescine and spermidine levels. As in other organisms, exogenous polyamines led to a decrease in the activity of ornithine decarboxylase, a key enzyme of polyamine synthesis. In contrast to mammalian cells, this polyamine-induced decrease in ornithine decarboxylase activity is not mediated by a polyamine-dependent degradation or inactivation, but exclusively due to a decreased synthesis of ornithine decarboxylase. Translation of ornithine decarboxylase mRNA, but not overall protein biosynthesis is slowed by increased polyamine levels. 相似文献
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Endogenous polyamine content of the ectomycorrhizal fungus Paxillus involutus , as well as the activity of its biosynthetic enzymes in relation to mycelia ageing were investigated in this work. Polyamines in free, PCA-soluble and insoluble conjugated forms, are present in Paxillus involutus mycelia in relatively high amounts and the ratio of putrescine to spermidine is age-dependent. Both arginine- and ornithine-decarboxylases are present, but putrescine biosynthesis proceeds mostly via ornithine decarboxylase and decreases with the age of mycelia. There was a large release of free polyamines from mycelia which showed age-dependent features. Clear polyamine uptake was observed in 2-wk-old mycelia and no competition between putrescine and cadaverine was detected. Putrescine uptake seems to reduce ornithine decarboxylase activity, but does not affect arginine decarboxylase. 相似文献
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多胺是普遍存在于生物体中的一种脂肪族阳离子胺。多胺通过离子键和氢键的形式与生物大分子结合,调节生物大分子的生物学活性,调控细胞的生长和发育。多胺对核酸的作用一直是关注热点,而针对蛋白质的影响目前研究较少。本文主要针对多胺调控代谢相关酶、通道蛋白质和其他功能性蛋白质以及相关规律和机制进行综述,并从蛋白质结构和功能角度探讨了多胺与蛋白质之间的相互作用关系,同时总结了多胺与蛋白质相互作用研究在疾病治疗中的应用前景和面临的问题。 相似文献
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R H Davis 《Journal of cellular biochemistry》1990,44(4):199-205
The management of polyamine synthesis and polyamine pools differs fundamentally from that of most other small molecular-weight endproducts. The polyamines are vital to growth and important cellular functions, but they are toxic in excess. I argue here that their multivalent cationic character, leading to binding to cell constituents, precludes fluent feedback inhibition of synthesis. This has led to the development of elaborate alternative regulatory mechanisms controlling ornithine decarboxylase, the key initial enzyme of the pathway. Poorly regulated polyamine synthesis and the toxicity of polyamines impose upon cells a need to control uptake and to dispose of excess polyamines. Recent data on polyamine transport suggest unorthodox mechanisms of accomplishing these functions. 相似文献
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Jürgen Manfred Knott 《FEBS letters》2009,583(21):3519-3524
Polyamines are ubiquitously present in all organisms. In addition to the common polyamines, thermophilic archaea synthesize long-chain polyamines. In the present study polyamine synthases from Hyperthermus butylicus and Pyrobaculum aerophilum were cloned and their substrate specificity was analyzed. The polyamine synthase HbSpeE II from H. butylicus synthesized long-chain polyamines with high activity using the same mechanism that is used by a wide range of organisms to synthesize common polyamines, in which the aminopropyl residue derives from decarboxylated S-adenosylmethionine. This is the first polyamine synthase described that synthesizes a polyamine longer than a tetramine with high activity. 相似文献
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Dong-Hun Bae Darius J.R. Lane Patric J. Jansson Des R. Richardson 《Biochimica et Biophysica Acta (BBA)/General Subjects》2018,1862(9):2053-2068
Polyamines are ubiquitous positively charged amines found in all organisms. These molecules play a crucial role in many biological functions including cell growth, gene regulation and differentiation. The three major polyamines produced in all mammalian cells are putrescine, spermidine and spermine. The intracellular levels of these polyamines depend on the interplay of the biosynthetic and catabolic enzymes of the polyamine and methionine salvage pathway, as well as the involvement of polyamine transporters. Polyamine levels are observed to be high in cancer cells, which contributes to malignant transformation, cell proliferation and poor patient prognosis. Considering the critical roles of polyamines in cancer cell proliferation, numerous anti-polyaminergic compounds have been developed as anti-tumor agents, which seek to suppress polyamine levels by specifically inhibiting polyamine biosynthesis, activating polyamine catabolism, or blocking polyamine transporters. However, in terms of the development of effective anti-cancer therapeutics targeting the polyamine system, these efforts have unfortunately resulted in little success. Recently, several studies using the iron chelators, O-trensox and ICL670A (Deferasirox), have demonstrated a decline in both iron and polyamine levels. Since iron levels are also high in cancer cells, and like polyamines, are required for proliferation, these latter findings suggest a biochemically integrated link between iron and polyamine metabolism. 相似文献
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Mst. Ara Gulshan Shigeyoshi Matsumura Tsunehiko Higuchi Naoki Umezawa 《Bioscience, biotechnology, and biochemistry》2018,82(8):1404-1407
Polyamines are a promising class of molecules that can modulate RNA enzyme activities. To analyze the effects of the number of amine moieties systematically, we employed four polyamines sharing dimethylene units to connect amine moieties. As a model RNA enzyme, we used a structurally unstable group I ribozyme, which was activated most and least efficiently by tetraethylenepentamine and diethylenetriamine respectively. 相似文献
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A. R. Khomutov T. A. Keinanen N. A. Grigorenko M. T. Hyvonen A. Uimari M. Pietila M. Cerrada-Gimenez A. R. Simonian M. A. Khomutov J. Vepsalainen L. Alhonen J. Janne 《Molecular Biology》2009,43(2):249-259
Biogenic amines spermine (Spm) and spermidine (Spd) are essential for cell growth. Polyamine analogs are widely used to investigate the enzymes of polyamine metabolism and the functions of spermine and spermidine in vitro and in vivo. It was demonstrated recently that α-methylated derivatives of Spm and Spd are able to fulfill the key cellular functions of polyamines, moreover, in some cases, the effects of (R) and (S) isomers were actually different. Using these α-methylated analogs of Spm and Spd, it turned possible to prevent the development of acute pancreatitis in SSAT-transgenic rats with controllable expression of the Spm/Spd N1-acetyltransferase gene. The analogs made it possible to reveal dormant stereospecificity of polyamine oxidase, Spm oxidase, and deoxyhypusine synthase. An original approach was suggested to regulate the stereospecificity of polyamine oxidase. Depletion of the intracellular polyamine pool was found to have both hypusine-related consequences and consequences unrelated to posttranslational modification of the eukaryotic translation initiation factor eIF5A. Possible applications of a new family of C-methylated polyamine analogs for the investigation and regulation of polyamine metabolism in vitro and in vivo are discussed. 相似文献
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Polyamine metabolism and cancer 总被引:7,自引:0,他引:7
Polyamines are aliphatic cations present in all cells. In normal cells, polyamine levels are intricately controlled by biosynthetic and catabolic enzymes. The biosynthetic enzymes are ornithine decarboxylase, S-adenosylmethionine decarboxylase, spermidine synthase, and spermine synthase. The catabolic enzymes include spermidine/spermine acetyltransferase, flavin containing polyamine oxidase, copper containing diamine oxidase, and possibly other amine oxidases. Multiple abnormalities in the control of polyamine metabolism and uptake might be responsible for increased levels of polyamines in cancer cells as compared to that of normal cells. This review is designed to look at the current research in polyamine biosynthesis, catabolism, and transport pathways, enumerate the functions of polyamines, and assess the potential for using polyamine metabolism or function as targets for cancer therapy. 相似文献
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Spermine block of the strong inward rectifier potassium channel Kir2.1: dual roles of surface charge screening and pore block
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Inward rectification in strong inward rectifiers such as Kir2.1 is attributed to voltage-dependent block by intracellular polyamines and Mg(2+). Block by the polyamine spermine has a complex voltage dependence with shallow and steep components and complex concentration dependence. To understand the mechanism, we measured macroscopic Kir2.1 currents in excised inside-out giant patches from Xenopus oocytes expressing Kir2.1, and single channel currents in the inside-out patches from COS7 cells transfected with Kir2.1. We found that as spermine concentration or voltage increased, the shallow voltage-dependent component of spermine block at more negative voltages was caused by progressive reduction in the single channel current amplitude, without a decrease in open probability. We attributed this effect to spermine screening negative surface charges involving E224 and E299 near the inner vestibule of the channel, thereby reducing K ion permeation rate. This idea was further supported by experiments in which increasing ionic strength also decreased Kir2.1 single channel amplitude, and by mutagenesis experiments showing that this component of spermine block decreased when E224 and E299, but not D172, were neutralized. The steep voltage-dependent component of block at more depolarized voltages was attributed to spermine migrating deeper into the pore and causing fast open channel block. A quantitative model incorporating both features showed excellent agreement with the steady-state and kinetic data. In addition, this model accounts for previously described substate behavior induced by a variety of Kir2.1 channel blockers. 相似文献
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A. R. Simonyan J. Vepsalainen A. R. Khomutov 《Russian Journal of Bioorganic Chemistry》2006,32(6):578-585
Convenient methods of synthesis of 1-aminooxy-3,8-diaza-11-aminoundecane, its earlier unknown N 1-and N 11-acetyl derivatives, and also 1,10-bis(aminooxy)-3,8-diazadecane are suggested. It is shown that it is possible to selectively delete the acid-labile ethoxyethylidene protection of aminooxy group by hydrosulfates in the presence of N-tert-butyloxycarbonyl group. 相似文献
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Implications and concepts of polyamine-nucleic acid interactions 总被引:7,自引:0,他引:7
Modeling, x-ray diffraction, and solution studies have contributed to the understanding of interactions between polyamines and nucleic acids. Polyamines stabilize a variety of unusual DNA structures and conformations in vitro, including both the left-handed Z and the right-handed A DNA. In addition, polyamines condense DNA and may be important in bending specific sequences. Investigations into the mechanisms of these effects provide support for both specific and nonspecific interactions between polyamines and DNA. Although exact relationships between the binding of polyamines and conformational changes in nucleic acids are still being clarified, polyamines remain important candidates for regulators of DNA conformation in vivo. 相似文献
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The primary free polyamines identified during growth and development of strawberry (Fragaria × ananassa Duch.) microcuttings cultivated in vitro were putrescine, spermidine and spermine. Polyamine composition differed according to tissue and stages of development; putrescine was predominant in aerial green tissues and roots. -DL-difluoromethylarginine (DFMA), a specific and irreversible inhibitor of the putrescine-synthesizing enzyme, arginine decarboxylase (ADC), strongly inhibited growth and development. Application of agmatine or putrescine to the inhibited system resulted in a reversal of inhibition, indicating that polyamines are involved in regulating the growth and development of strawberry microcuttings. -DL-difluoromethylornithine (DFMO), a specific and irreversible inhibitor of putrescine biosynthesis by ornithine decarboxylase, promoted growth and development. We propose that ADC regulates putrescine biosynthesis during microcutting development. The application of exogenous polyamines (agmatine, putrescine, spermidine) stimulated development and growth of microcuttings, suggesting that the endogenous concentrations of these polyamines can be growth limiting.Abbreviations ADC
arginine decarboxylase
- ODC
ornithine decarboxylase
- DFMA
-difluoromethylarginine
- DFMO
-difluoromethylornithine
- Put
putrescine
- Spd
spermidine
- Sp
spermine
- DW
dry weight
- PA
polyamine
- PPF
photosynthetic photon flux 相似文献
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在东海赤潮爆发区域运用围隔生态系实验方法,研究了不同营养盐条件下围隔生态系内多胺浓度变化。结果表明:2010年选用东海原甲藻赤潮爆发处海水,东海原甲藻是各围隔生态系内主要优势种,没有种群演替现象发生。两种营养盐添加方式下各围隔内精胺浓度维持较高水平,都呈现先波折下降后波折上升的趋势,与东海原甲藻的生长变化正好相反;各围隔内腐胺浓度水平较高,变化起伏较大,其中有两个实验组腐胺整体变化趋势与东海原甲藻生长趋势类似;所有围隔内亚精胺浓度最低,波动较小。2011年取用中肋骨条藻赤潮爆发处海水,所有围隔生态系内优势种都发生了从中肋骨条藻到东海原甲藻的演替。各围隔生态系内腐胺浓度最高,在中肋骨条藻生长初期腐胺浓度下降,随着中肋骨条藻的生长有所上升,实验后期随着东海原甲藻的生长又整体呈现出下降趋势;各实验组精胺浓度较低,在中肋骨条藻消亡东海原甲藻出现的种群演替期间,都呈现出较大波动;各围隔内亚精胺浓度较低,在整个种群演替过程中没有明显的变化。围隔生态系中补充营养盐,通过对浮游植物生长的影响,间接影响围隔生态系内的多胺变化。 相似文献
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Ariadna Peremarti Ludovic Bassie Paul Christou Teresa Capell 《Plant molecular biology》2009,70(3):253-264
Polyamines are known to play important roles in plant stress tolerance but it has been difficult to determine precise functions
for each type of polyamine and their interrelationships. To dissect the roles of putrescine from the higher polyamines spermidine
and spermine, we generated transgenic rice plants constitutively expressing a heterologous S-adenosylmethionine decarboxylase (SAMDC) gene from Datura stramonium so that spermidine and spermine levels could be investigated while maintaining a constant putrescine pool. Whereas transgenic
plants expressing arginine decarboxylase (ADC) produced higher levels of putrescine, spermidine and spermine, and were protected from drought stress, transgenic plants
expressing SAMDC produced normal levels of putrescine and showed drought symptoms typical of wild type plants under stress,
but the transgenic plants showed a much more robust recovery on return to normal conditions (90% full recovery compared to
25% partial recovery for wild type plants). At the molecular level, both wild type and transgenic plants showed transient
reductions in the levels of endogenous ADC1 and SAMDC mRNA, but only wild type plants showed a spike in putrescine levels under stress. In transgenic plants, there was no spike
in putrescine but a smooth increase in spermine levels at the expense of spermidine. These results confirm and extend the
threshold model for polyamine activity in drought stress, and attribute individual roles to putrescine, spermidine and spermine. 相似文献