Biogenic Polyamines Spermine Research Articles

Inhibition of nicotinic acetylcholine receptors by oligoarginine peptides and polyamine-related compounds.

Oligoarginine peptides, known mostly for their cell-penetrating properties, are also inhibitors of the nicotinic acetylcholine receptors (nAChRs). Since octa-arginine (R8) inhibits α9α10 nAChR and suppresses neuropathic pain, we checked if other polycationic compounds containing amino and/or guanidino groups could be effective and tested the activity of the disulfide-fixed "cyclo"R8, a series of biogenic polyamines (putrescine, spermidine, and spermine), C-methylated spermine analogs, agmatine and its analogs, as well as acylpolyamine argiotoxin-636 from spider venom. Their inhibitory potency on muscle-type, α7 and α9α10 nAChRs was determined using radioligand analysis, electrophysiology, and calcium imaging. "Cyclo"R8 showed similar activity to that of R8 against α9α10 nAChR (IC50 ≈ 60nM). Biogenic polyamines as well as agmatine and its analogs displayed low activity on muscle-type Torpedo californica, as well as α7 and α9α10 nAChRs, which increased with chain length, the most active being spermine and its C-methylated derivatives having IC50 of about 30μM against muscle-type T. californica nAChR. Argiotoxin-636, which contains a polyamine backbone and terminal guanidino group, also weakly inhibited T. californica nAChR (IC50 ≈ 15μM), but it revealed high potency against rat α9α10 nAChR (IC50 ≈ 200nM). We conclude that oligoarginines and similar polycationic compounds effectively inhibiting α9α10 nAChR may serve as a basis for the development of analgesics to reduce neuropathic pain.

Evaluation of the Cytotoxic Effect of Pd2Spm against Prostate Cancer through Vibrational Microspectroscopies.

Regarding the development of new antineoplastic agents, with a view to assess the selective antitumoral potential which aims at causing irreversible damage to cancer cells while preserving the integrity of their healthy counterparts, it is essential to evaluate the cytotoxic effects in both healthy and malignant human cell lines. In this study, a complex with two Pd(II) centers linked by the biogenic polyamine spermine (Pd2Spm) was tested on healthy (PNT-2) and cancer (LNCaP and PC-3) prostate human cell lines, using cisplatin as a reference. To understand the mechanisms of action of both cisplatin and Pd2Spm at a molecular level, Fourier Transform Infrared (FTIR) and Raman microspectroscopies were used. Principal component analysis was applied to the vibrational data, revealing the major metabolic changes caused by each drug, which were found to rely on DNA, lipids, and proteins, acting as biomarkers of drug impact. The main changes were observed between the B-DNA native conformation and either Z-DNA or A-DNA, with a higher effect on lipids having been detected in the presence of cisplatin as compared to Pd2Spm. In turn, the Pd-agent showed a more significant impact on proteins.

Effect of Exogenous Spermine on Biofilm Formation in Mycobacteria by Stimulating the Synthesis of Glycopeptidolipids

Biofilm formation is of great interest by its ability to increase bacterial tolerance to antibiotics that represent a serious problem for modern medicine. Among mycobacteria, which are also capable of forming biofilms, there are pathogens of socially dangerous infections, including tuberculosis. Basing on these data, the strains of Mycolicibacterium smegmatis mc2 155 were chosen as the objects of this study, including the parent strain without deletions and its mutants with one (ΔrelMsm) and double (ΔrelMsmΔrelZ) chromosomal deletions of the genes responsible for the synthesis of alarmone synthetase enzymes. Biofilms of mutant strains exhibited defects in biofilm formation. We have shown that the integrity, hydrophobicity, and the level of biomass of surface mycobacterial biofilms are dependent on the amount of glycopeptidolipids (GPL) in cells. The level of GPL depends on the activity of alarmone synthetases. The biogenic polyamine spermine is able to enhance the production of GPLs, restoring the integrity of biofilms of mutant strains. It is possible that this effect of spermine is caused by the influence on the activity of mycobacterial alarmone synthetases, which makes promising the further studying the molecular mechanisms of its action.

Polyamines and ethylene action blocker (STS) effectively augment longevity and postharvest attributes in isolated flowers of Digitalis purpurea L.

The present investigation focused on the study of the exogenous inclusion of anti-senescence biogenic polyamines (putrescine, spermidine and spermine) and ethylene antagonist silver thiosulphate on flower longevity and postharvest performance in excised flowers of Digitalis purpurea L. At one day before anthesis stage, isolated buds of Digitalis purpurea were transported to the laboratory in distilled water. The samples were divided into five sets with one set of flower buds (i.e., control) held in distilled water. The remaining four sets were respectively supplied with 0.5, 1 and 1.5 mM of putrescine (PUT), 0.1, 0.2 and 0.3 mM of spermidine (SPD), 0.2, 0.4 and 0.6 mM of spermine (SPM), 0.1, 0.2 and 0.3 mM of silver thiosulphate (STS). The inclusion of polyamines and STS in holding solutions enhanced the flower longevity of D. purpurea significantly compared to the control. The results indicated that the flower longevity of 14 days was recorded in 0.4 mM of spermine, followed by 13 days in 1 mM PUT, 12.5 days in 0.2 mM SPD and 12 days in 0.2 mM STS. This enhanced flower longevity corroborated with the higher values of soluble proteins, total sugars, floral diameter and membrane stability index. The improved flower longevity was also found to be positively associated with increased activities of various antioxidant enzymes viz., superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APX) and reduced activity of lipoxygenase (LOX). The flowers supplemented with different treatments retained a lower phenolic content than the control. This research concluded that polyamines and STS have a profound impact on the flower longevity of Digitalis flowers. SPM was found to be a more potential polyamine in augmenting the postharvest performance in isolated flowers of D. purpurea.

Recent Advances in Fluorescent Methods for Polyamine Detection and the Polyamine Suppressing Strategy in Tumor Treatment.

The biogenic aliphatic polyamines (spermine, spermidine, and putrescine) are responsible for numerous cell functions, including cell proliferation, the stabilization of nucleic acid conformations, cell division, homeostasis, gene expression, and protein synthesis in living organisms. The change of polyamine concentrations in the urine or blood is usually related to the presence of malignant tumors and is regarded as a biomarker for the early diagnosis of cancer. Therefore, the detection of polyamine levels in physiological fluids can provide valuable information in terms of cancer diagnosis and in monitoring therapeutic effects. In this review, we summarize the recent advances in fluorescent methods for polyamine detection (supramolecular fluorescent sensing systems, fluorescent probes based on the chromophore reaction, fluorescent small molecules, and fluorescent nanoparticles). In addition, tumor polyamine-suppressing strategies (such as polyamine conjugate, polyamine analogs, combinations that target multiple components, spermine-responsive supramolecular chemotherapy, a combination of polyamine consumption and photodynamic therapy, etc.) are highlighted. We hope that this review promotes the development of more efficient polyamine detection methods and provides a comprehensive understanding of polyamine-based tumor suppressor strategies.

Identification of a Novel Substrate-Derived Spermine Oxidase Inhibitor.

Homeostasis of the biogenic polyamines spermine (Spm) and spermidine (Spd), present in μM-mM concentrations in all eukaryotic cells, is precisely regulated by coordinated activities of the enzymes of polyamine synthesis, degradation, and transport, in order to sustain normal cell growth and viability. Spermine oxidase (SMOX) is the key and most recently discovered enzyme of polyamine metabolism that plays an essential role in regulating polyamine homeostasis by catalyzing the back-conversion of Spm to Spd. The development of many types of epithelial cancer is associated with inflammation, and disease-related inflammatory stimuli induce SMOX. MDL72527 is widely used in vitro and in vivo as an irreversible inhibitor of SMOX, but it is also potent towards N1-acetylpolyamine oxidase. Although SMOX has high substrate specificity, Spm analogues have not been systematically studied as enzyme inhibitors. Here we demonstrate that 1,12-diamino-2,11-bis(methylidene)-4,9-diazadodecane (2,11-Met2-Spm) has, under standard assay conditions, an IC50 value of 169 μM towards SMOX and is an interesting instrument and lead compound for studying polyamine catabolism.

C-Methylated Analogs of Spermine and Spermidine: Synthesis and Biological Activity

Biogenic polyamines spermine and spermidine are present in eukaryotic cells in micro- and millimolar concentrations, that determines the multiplicity of their functions and the necessity to support normal cell growth. Analogs and derivatives of spermine and spermidine are widely used in biochemistry of polyamines, a number of fundamentally significant results for the field were obtained with their help. C-methylated analogs of polyamines are unique, since among these compounds functionally active in vitro and in vivo spermidine and spermine mimetics were found. Biochemical properties of the compounds of this family can be regulated by moving the methyl group along the backbone of a polyamine and/or changing the configuration of the chiral center. The peculiarities of the interaction of C-methylated analogs of polyamines with the enzymes of their metabolism, the activity in the cell culture and the methods of synthesizing these compounds are discussed.

The Regulatory Effect of Biogenic Polyamines Spermine and Spermidine in Men and Women

Background—The incidence and prevalence of infertility and sexual dysfunction in men and women is increasing. The biogenic polyamines spermine and spermidine are important for sexual function as well as fertility. Spermine and spermidine are present in plant foods and synthesized from ornithine and methionine in mammals. Stress and stress-associated hormone disruption are contributors to both poor sexual function and infertility. Spermine and spermidine are important in reducing the impact of stress on living organisms. Objective—This open-label pilot trial was designed to determine the impact of spermine and spermidine supplementation on hormone levels of otherwise healthy human subjects with no history of infertility or sexual dysfunction over a 30-day period. Pre and post supplement levels of cortisol, DHEAS, testosterone, progesterone and estradiol as well as 30-day post supplement levels of these hormones were performed on age/gender equivalent subjects. A total of 15 individuals participated in the study. Informed consent forms were executed along, with adverse events reporting information. Results—Clinically significant reductions (p-value less than 0.05) in cortisol were seen in 30 days among 83% of male participants and 37% of female participants. Sixty-six percent of male participants maintained lower cortisol levels 30 days after withdrawal of the study supplement. In women, the cumulative effect of the spermine and spermidine supplementation continued with 50% reporting a significant reduction in cortisol levels 30 days after withdrawal of the study supplement. There was an average of 3.3 pounds of weight loss during the first 30 days of supplementation without any dietary or metabolic intervention. Further, 7 out of 8 female participants demonstrated a moderate increase in DHEAS at 30 days, while 5 out of 7 male participants demonstrated a significant Dehydroepiandrosterone (DHEAS) increase in 60 days. Eighty-three percent of men had a decrease in estradiol and 100% of men had a decrease of progesterone at 30 days while 75% of women in follicular phase experienced both an increase in estradiol and a significant increase in progesterone. In the men under 50 years age group, testosterone levels increased by an average of 48.9% (28.3 pg/mL), while in the over 50 age group, testosterone levels decreased by a mean average of 36.7% (33 pg/mL). In women, 75% had an average increase of 48.8% (10.6 pg/mL) in testosterone levels at 30 days while the same number (75%) had an average decrease of 32.7% (10.5 pg/mL) in testosterone levels at 60 days. Conclusion—For both fertility and sexual performance, it is important to reduce cortisol levels. Also important to fertility is the balancing of various hormone ratios during reproductive years. Likewise, it is important for sexual performance of women post-menopause and men post-andropause to achieve cortisol reduction and hormone balance. The biogenic polyamines spermine and spermidine appear to support a trend toward hormone balance, though a larger trial is needed to confirm this conclusion.

Hepatitis C Virus Alters Metabolism of Biogenic Polyamines by a ROS-dependent Induction of Key Enzymes of Their Metabolism

Hepatitis C virus (HCV) infection often sets a chronic liver disease leading to fibrosis and hepatocellular carcinoma. These and other pathologies are induces by the virus by several mechanisms including pronounced oxidative stress and metabolic alterations. Though biogenic polyamines spermine and spermidine play pivotal role in liver functioning and even scavenging ROS, interplay between their metabolism and HCV infection has not been studied so far. Metabolism of spermine and spermidine is regulated mostly by three enzymes: ornithine decarboxylase (ODC) involved in their biosynthesis and by catabolic enzymes spermidine/spermine-N1-acetyl transferase (SSAT) and spermine oxidase (SMO). We have shown that chemically-induces oxidative stress triggers induction of ODC and SSAT via Nrf2 transcription factor. In lines with this, transient expression of two viral proteins, capsid and NS5A triggers a transient induction of both ODC and SSAT. In addition, both HCV core and NS5A induce sustained expression of spermine oxidase (SMO) in a ROS-independent fashion. Human hepatocarcinoma Huh7 cells harboring a full-length HCV replicon exhibited suppressed ODC and SSAT levels and elevated levels of SMO as well as depleted intracellular levels of spermine and spermidine. Noteworthy, SMO is a H2O2-producing enzyme implicated in development of gastric and colon cancer. Thus, role of HCV-induced SMO expression and of other alterations of polyamine metabolism in HCV replication and development of virus-associated liver pathologies should be explored in future.

Nanocomposite biomimetic vesicles based on interfacial complexes of polyelectrolytes and colloid magnetic nanoparticles

Development and study of novel biomimetic and biocompatible functional nanofilm structures, surfaces and colloid membranous vesicles are currently important from fundamental and applied viewpoints. They can serve as model systems for insight into the basic structural-functional interconnections and physicochemical mechanisms at the nano-scale in biomembranous systems, and are useful for development of engineering solutions efficient for bio-medical applications including controlled drug delivery. We present here the results of a study of novel nanofilm composite structures (Langmuir monolayers, Langmuir-Blodgett films and liposomes) based on the interfacial complexes formed by biogenic lipid phosphatidylcholine, synthetic amphiphilic water-insoluble polyamine stearoylspermine (a derivative of biogenic polyamine spermine and stearic acid), colloid cationic ligand-free magnetite nanoparticles and polyanions (DNA, Poly(styrenesulfonate)). It was found that stearoylspermine molecules formed stable Langmuir monolayer on an aqueous subphase surface and that monolayer compression isotherm changed as a result of interactions of the stearoylspermine monolayer with aqueous subphase components (colloid cationic magnetite nanoparticles and polyanions). Monolayer Langmuir-Blodgett films of interfacial polycomplexes formed by stearoylspermine and magnetite nanoparticles or DNA molecules were deposited onto the mica substrate surface and the structure of polycomplex films was investigated using AFM. The data obtained using Langmuir monolayer technique were further used in formation of new composite nanofilm magnetic colloidal membranous vesicles based on the interfacial polycomplexes of phosphatidylcholine, stearoylspermine, magnetite nanoparticles and polyanions. The nanocomposite membranous vesicles were prepared successfully by sequential adsorption of colloid cationic ligand-free magnetite nanoparticles and polyanions onto the cationic surface of mixed phosphatidylcholine/stearoylspermine liposomes preliminarily formed using conventional ultrasound method. The formed vesicles were characterized by transmission electron microscopy, AFM, electron magnetic resonance technique, laser light scattering and electrophoresis techniques. The synthesized stable biocompatible nanocomposite magnetic liposomal vesicles can be useful in development of novel efficient systems for capsulation, targeted transport, controlled spatial localization and physical stimuli-addressed drug and DNA delivery.

Hepatitis C virus alters metabolism of biogenic polyamines by affecting expression of key enzymes of their metabolism

Chronic infection with hepatitis C virus (HCV) induces liver fibrosis and cancer. In particular metabolic alterations and associated oxidative stress induced by the virus play a key role in disease progression. Albeit the pivotal role of biogenic polyamines spermine and spermidine in the regulation of liver metabolism and function and cellular control of redox homeostasis, their role in the viral life cycle has not been studied so far. Here we show that in cell lines expressing two viral proteins, capsid and the non-structural protein 5A, expression of the two key enzymes of polyamine biosynthesis and degradation, respectively, ornithine decarboxylase (ODC) and spermidine/spermine-N1-acetyl transferase (SSAT), increases transiently. In addition, both HCV core and NS5A induce sustained expression of spermine oxidase (SMO), an enzyme that catalyzes conversion of spermine into spermidine. Human hepatoma Huh7 cells harboring a full-length HCV replicon exhibited suppressed ODC and SSAT levels and elevated levels of SMO leading to decreased intracellular concentrations of spermine and spermidine. Thus, role of HCV-driven alterations of polyamine metabolism in virus replication and development of HCV-associated liver pathologies should be explored in future.

Anti-Invasive and Anti-Proliferative Synergism between Docetaxel and a Polynuclear Pd-Spermine Agent.

The present work is aimed at evaluating the antitumour properties of a Pd(II) dinuclear complex with the biogenic polyamine spermine, by investigating: i) the anti-angiogenic and anti-migration properties of a Pd(II) dinuclear complex with spermine (Pd2Spm); ii) the anti-proliferative activity of Pd2Spm against a triple negative human breast carcinoma (MDA-MB-231); and finally iii) the putative interaction mediated by combination of Pd2Spm with Docetaxel. Anti-invasive (anti-angiogenic and anti-migratory) as well as anti-proliferative capacities were assessed, for different combination schemes and drug exposure times, using the CAM assay and VEGFR2 activity measurement, the MatrigelTM method and the SRB proliferation test. The results thus obtained evidence the ability of Pd2Spm to restrict angiogenesis and cell migration: Pd2Spm induced a marked inhibition of migration (43.8±12.2%), and a higher inhibition of angiogenesis (81.8±4.4% for total length values, at 4 μM) as compared to DTX at the clinical dosage 4x10-2 μM (26.4±14.4%; n = 4 to 11). Combination of Pd2Spm/DTX was more effective as anti-invasive and anti-proliferative than DTX or Pd2Spm in sole administration, which is compatible with the occurrence of synergism: for the anti-angiogenic effect, IC50(Pd2Spm/DTX) = 0.5/0.5x10-2 μM vs IC50(DTX) = 1.7x10-2 μM and IC50(Pd2Spm) = 1.6 μM. In conclusion, the reported effects of Pd2Spm on angiogenesis, migration and proliferation showed that this compound is a promising therapeutic agent against this type of breast cancer. Moreover, combined administration of Pd2Spm and DTX was found to trigger a substantial synergetic effect regarding angiogenesis inhibition as well as anti-migratory and anti-proliferative activities reinforcing the putative use of Pd(II) complexes in chemotherapeutic regimens. This is a significant outcome, aiming at the application of these combined strategies towards metastatic breast cancer (or other type of resistant cancers), justifying further studies that include pre-clinical trials.

Conjugation of biogenic and synthetic polyamines with serum proteins: A comprehensive review

We have reviewed the conjugation of biogenic polyamines spermine (spm), spermidine (spmd) and synthetic polyamines 3,7,11,15-tetrazaheptadecane.4HCl (BE-333) and 3,7,11,15,19-pentazahenicosane.5HCl (BE-3333) with human serum albumin (HSA), bovine serum albumin (BSA) and milk beta-lactoglobulin (b-LG) in aqueous solution at physiological pH. The results of multiple spectroscopic methods and molecular modeling were analysed here and correlations between polyamine binding mode and protein structural changes were estabilished. Polyamine-protein bindings are mainly via hydrophilic and H-bonding contacts. BSA forms more stable conjugates than HSA and b-LG. Biogenic polyamines form more stable complexes than synthetic polyamines except in the case of b-LG, where the protein shows more hydrophobic character than HSA and BSA. The loading efficacies were 40⿿52%. Modeling showed the presence of several H-bonding systems, which stabilized polyamine-protein conjugates. Polyamine conjugation induced major alterations of serum protein conformations. The potential application of serum proteins in delivery of polyamines is evaluated here.

Conjugation of chitosan nanoparticles with biogenic and synthetic polyamines: A delivery tool for antitumor polyamine analogues

We report the conjugation of chitosan nanoparticles with biogenic polyamines spermine (spm), spermidine (spmd) and synthetic polyamines 3,7,11,15-tetrazaheptadecane.4HCl (BE-333) in aqueous solution. Multiple spectroscopic methods, thermodynamic parameters and molecular modeling were used to analyse polyamine bindings to chitosan nanoparticles. Thermodynamic parameters ΔS, ΔH and ΔG showed that polyamines bind protein through H-bonding and hydrophobic contacts with biogenic polyamines form more stable conjugates than synthetic polyamines. As polymer size increases the stability of polyamine-chitosan conjugate increases. The loading efficacy was 40–50% for polyamine-chitosan conjugates. Modeling showed that polyamine-protein interaction is spontaneous and chitosan nanoparticles can be used for delivery of antitumor polyamine analogues.

Thermodynamic analysis of biogenic and synthetic polyamines conjugation with PAMAM-G4 nanoparticles

We report the thermodynamic analysis of the bindings of poly(amidoamine) (PAMAM-G4) nanoparticles with biogenic polyamines spermine (spm), spermidine (spmd) and synthetic polyamines 3,7,11,15-tetrazaheptadecane·4HCl (BE-333) in aqueous solution at physiological conditions. Multiple spectroscopic methods, thermodynamic parameters and molecular modelling were used to analyse polyamine bindings to PAMAM dendrimers. Thermodynamic parameters ΔS, ΔH and ΔG parameters showed that polyamines bind polymer through H-bonding and van der Waals contacts with biogenic polyamines form more stable conjugates than synthetic polyamines. Modelling showed that polyamines are located at the surface of PAMAM with the free binding energy of −3.56 (spermine), −3.88 (spermidine) and −3.13kcal/mol (BE-333), indicating spontaneous polyamine–polymer interaction at room temperature.

Protective action of spermine and spermidine against photoinhibition of photosystem I in isolated thylakoid membranes.

The photo-stability of photosystem I (PSI) is of high importance for the photosynthetic processes. For this reason, we studied the protective action of two biogenic polyamines (PAs) spermine (Spm) and spermidine (Spd) on PSI activity in isolated thylakoid membranes subjected to photoinhibition. Our results show that pre-loading thylakoid membranes with Spm and Spd reduced considerably the inhibition of O2 uptake rates, P700 photooxidation and the accumulation of superoxide anions (O2 −) induced by light stress. Spm seems to be more effective than Spd in preserving PSI photo-stability. The correlation of the extent of PSI protection, photosystem II (PSII) inhibition and O2 − generation with increasing Spm doses revealed that PSI photo-protection is assumed by two mechanisms depending on the PAs concentration. Given their antioxidant character, PAs scavenge directly the O2 − generated in thylakoid membranes at physiological concentration (1 mM). However, for non-physiological concentration, the ability of PAs to protect PSI is due to their inhibitory effect on PSII electron transfer.

Amine oxidase-based biosensors for spermine and spermidine determination.

The present work describes the development and optimization of electrochemical biosensors for specific determination of the biogenic polyamine spermine (Spm) and spermidine (Spmd) whose assessment represents a novel important analytical tool in food analysis and human diagnostics. These biosensors have been prepared using novel engineered enzymes: polyamine oxidase (PAO) endowed with selectivity towards Spm and Spmd and spermine oxidase (SMO) characterized by strict specificity towards Spm. The current design entails biosensors in which the enzymes were entrapped in poly(vinyl alcohol) bearing styrylpyridinium groups (PVA-SbQ), a photocrosslinkable gel, onto an electrode surface. Screen-printed electrodes (SPEs) were used as electrochemical transducers for enzymatically produced hydrogen peroxide, operating at different potential vs Ag/AgCl according to the material of the working electrode (WE): +700mV for graphite (GP) or -100mV for Prussian blue (PB)-modified SPE, respectively. Biosensor performances were evaluated by means of flow injection amperometric (FIA) measurements. The modified electrodes showed good sensitivity, long-term stability and reproducibility. Under optimal conditions, the PAO biosensor showed a linear range 0.003-0.3mM for Spm and 0.01-0.4mM for Spmd, while with the SMO biosensor, a linear range of 0.004-0.5mM for Spm has been obtained. The main kinetic parameters apparent Michaelis constant (K M), turnover number (K cat) and steady-state current (I max) were determined. The proposed device was then applied to the determination of biogenic amines in blood samples. The results obtained were in good agreement with those obtained with the GC-MS reference method.

Effect of biogenic polyamine spermine on the structure and function of photosystem I

We located the binding sites of spermine (Spm) to PSI sub-membrane proteins and the impact of this interaction on the photoprotection of PSI activity, using spectroscopic methods and molecular modeling. Our results showed that at high Spm content the polyamine binds PSI polypeptides through H-bonding and induces major protein conformational changes with the reduction of α-helix from 52% to 42% and an increase of the β-sheet from 26% to 29%. However, polyamine does not affect significantly the photooxidizable P700 in control sample and considerably protects it against strong illumination. On the contrary, protein conformational changes coincide with an important inhibition of O2 uptake rates by polyamine, which revealed that the protein of the PSI donor side plastocyanin is a main target for Spm inhibition. The photoprotection of PSI photochemical activity may be due to the stabilization of the PSI stromal polypeptides by Spm as shown by the docking results. Spm binds to different amino acids with hydrophilic and hydrophobic characters, while the presence of several H-bondings stabilizes Spm–PSI complexation.

Hydroxylamine derivatives for regulation of spermine and spermidine metabolism

The biogenic polyamines spermine, spermidine, and their precursor putrescine are present in micro-to-millimolar concentrations in all cell types and are vitally important for their normal growth. High intracellular content of spermine and spermidine determines the multiplicity of the cellular functions of the polyamines. Many of these functions are not well characterized at the molecular level, ensuring the ongoing development of this field of biochemistry. Tumor cells have elevated polyamine level if compared with normal cells, and this greatly stimulates the search for new opportunities to deplete the intracellular pool of spermine and spermidine resulting in decrease in cell growth and even cell death. O-Substituted hydroxylamines occupy their own place among chemical regulators of the activity of the enzymes of polyamine metabolism. Varying the structure of the alkyl substituent made it possible to obtain within one class of chemical compounds highly effective inhibitors and regulators of the activity of all the enzymes of putrescine, spermine and spermidine metabolism (with the exception of FAD-dependent spermine oxidase and acetylpolyamine oxidase), effectors of the polyamine transport system, and even actively transported in cells "proinhibitor" of ornithine decarboxylase. Some principles for the design of specific inhibitors of these enzymes as well as the peculiarities of cellular effects of corresponding O-substituted hydroxylamines are discussed.

Thermodynamics of the DNA binding of biogenic polyamines: Calorimetric and spectroscopic investigations

The thermodynamics of the reaction of biogenic polyamines spermine, spermidine, putrescine and cadaverine with calf thymus DNA was studied by thermal melting, differential scanning calorimetry and isothermal titration calorimetry experiments. These results were supplemented by ethidium bromide displacement and circular dichroism experiments. Melting studies show enhanced stabilization of DNA melting temperature by spermine (17K)>spermidine (11K)>putrescine (7K)>cadaverine (6K). The binding affinity of the polyamines to DNA as determined from calorimetry experiments was in the order, spermine>spermidine>putrescine>cadaverine with KiSPM=6.20×105M−1, KiSPD=3.10×105M−1, KiPUT=1.80×104M−1, and KiCAD=1.60×104M−1 at T=293.15K, which correlated with their increasing number of positive charges. The trend in the binding affinity was also in agreement with the IC50 values of ethidium bromide displacement ability and circular dichroism perturbations. Absorbance and circular dichroism studies showed perturbation of DNA conformation within the B-form by spermine to be the highest and that by cadaverine to be the least. The binding of all the four polyamines was entropy driven with small enthalpy contributions that were unfavourable. Electrostatic interaction is judged to be the major contributing force to the Gibbs energy term. The heat capacity values denote some extent of hydrophobic interaction between the polyamines and DNA.