Filtry
wszystkich: 41
Wyniki wyszukiwania dla: ADDUKTY%20DNA
-
Isolation and structure of a covalent cross-link adduct between mitomycin C and DNA **1987 VOL.235 S. 1204-1208, 5 RYS. BIBLIOGR. 37 POZ.//
PublikacjaA DNA cross-link adduct of the antitumor agent mitomycin C (MC) to DNA has been isolated and characterized; the results provide direct proof for bifunctional alkylation of DNA by MC. Exposure of MC to Micrococcus luteus DNA under reductive conditions and subsequent nuclease digestion yielded adducts formed between MC and deoxyguanosine residues. In addition to the two known monoadducts, a bisadduct was obtained. Reductive MC activation...
-
Phosphinophosphoranes: Mixed-Valent Phosphorus Compounds with Ambiphilic Properties
PublikacjaHerein, we present a simple synthesis of mixed-valent phosphinophosphoranes bearing three- and five-coordinate phosphorus centers. Compounds with phosphorus–phosphorus bonds were synthesized via a reaction of lithium phosphides RR′PLi with cat2PCl (cat = catecholate), whereas derivatives with methylene-linked phosphorus centers were obtained via a reaction of phosphanylmethanides RR′CH2Li with cat2PCl. The presence of accessible...
-
DNA restriction analysis as a supportive tool in mechanistic studies carried out by 32P-postlabelling
PublikacjaNumerous antitumor and carcinogenic compounds are able to modify DNA by forming covalent bonds with its constituents, while some anticarcinogenic compounds are known to prevent such a modification. All these processes are of vital biological import_ance, though deeper inside into factors influencing formation of DNA adducts is difficult due to the low level of their occurrence. 32P-Postlabelling approach ensures very sensitive...
-
Covalent DNA modification by products of myrosinase catalysed glucosinolate degradation in cell-free system
PublikacjaThe bioactive phytochemicals found in Brassica vegetables belonging to glucosinolates (GLS) and especially the products of their degradation isothiocyanates (ITC) and indoles are regarded as the most promising cancer chemopreventive compounds. These secondary metabolites constitute defence system repelling or preventing the development of agrophages attacking brassica plants. The antibiological properties of these compounds suggest...
-
Tetrakis(m2-methanol-k2O:O)bis(methanol-kO)-(m2-tri-tert-butoxysilane-thiolato-k3S:O,S)-bis(tri-tert-butoxysilanethiolato-k2O,S)-tetrasodium(i)
PublikacjaZwiązek [Na4(C12H27O3SSi)4(CH4O)6] jest rozpatrywany jako addukt trzech jonów - dwujądrowego kationu [Na2(MeOH)6]2+ oraz dwóch anionów [Na{SSi(OtBu)3}2] - utworzony dzięki istnieniu krótkich kontaktów pomiędzy tymi jonami.Obecność mostków siarczkowych i tlenkowych oraz wiązań wodorowych O-H...O and O-H...S, sprawia, że w rezultacie wszystkie atomy Na w czterojądrowym kompleksie są pięciokoordynacyjne.
-
Azomacrocyclic derivatives of imidazole: synthesis, structure, and metal ion complexation properties
PublikacjaOtrzymano nowe azokorony zawierające resztę imidazolu w makropierścieniu. Na drodze sprzęgania z solami diazoniowymiotrzymano pochodne imidazolu 2-metylo, 4-metylo oraz 4-fenyloimidazolu. Synteza była prowadzona w warunkach wysokiego ciśnienia. Dla 21-członowej pochodnej 4-metyloimidazolu określono strukturę jej adduktu z wodą przy pomocy metod rentgenograficznych.Zdolność kompleksowania jonów metali badano spektrofotometrycznie...
-
Diphosphination of CO2 and CS2 mediated by frustrated Lewis pairs - catalytic route to phosphanyl derivatives of formic and dithioformic acid
PublikacjaThe first example of CO2 diphosphination is described. Reactions of unsymmetrical diphosphanes with CE2 (E = O, S) catalyzed by BPh3 insert a CE2 molecule into the P-P bond with formation of the products of the general formula R2P-E-C(=E)-PR2. The obtained CO2 adducts arise from synergistic interaction of diphosphane and borane with CO2 molecule.
-
Phosphinoborinium cation: a synthon for cationic B-P bond systems
PublikacjaHerein, we report access to phosphinoborinium cations via heterolytic cleavage of the boron-bromide bond in bromophosphinoborane. The product of the reaction was isolated as a dimeric dication possessing a planar P2B2 core. Activation of C-H and C-P bonds in the dication led to formation of the borinium-phosphaborene adduct. Reactivity studies revealed that title cation exhibits ambiphilic properties and intramolecular frustrated...
-
Oznaczanie neurotoksyny, β-N-metylamino-L-alaniny (BMAA), w materiale biologicznym
Publikacjaβ-N-metylamino-L-alaniny (BMAA) jest naturalnie występującym niebiałkowym aminokwasem. W strukturze związku występuje grupa karboksylowa o pKa1 2,1 , pierwszorzędowa grupa aminowa o pKa2 6,5 i drugorzędowa grupa aminowa o pKa3 9,8. Przy fizjologicznych wartościach pH (7,4), w obecności CO2/HCo3-, BMAA tworzy węglanowe addukty (BMAA-α - NCO2 i BMAA-β-NCO2) o działaniu agonistycznym względem receptorów glumatinianu. Efektem jest...
-
The extended version of restriction analysis approach for the examination of the ability of low-molecular-weight compounds to modify DNA in a cell-free system
PublikacjaOne of the primary requirements in toxicology is the assessment of ability of chemicals to induce DNA covalent modification. There are several well-established methods used for this purpose such as 32P-Postlabeling or HPLC-MS. However, all of these approaches have difficult to overcome limitations, which prevents their use in genotoxin screening. Here, we describe the simple protocol exploiting specificity of restriction enzymes...