Non-enzymic in vitro formation of nitrosamines by bacteria isolated from meat products

1972 ◽  
Vol 18 (12) ◽  
pp. 1968-1971 ◽  
Author(s):  
D. L. Collins-Thompson ◽  
N. P. Sen ◽  
B. Aris ◽  
L. Schwinghamer
Keyword(s):  
Sodium Nitrite ◽  
Meat Products ◽  
Secondary Amines ◽  
Streptococcus Species ◽  
Metabolic Products ◽  
Ph Dependent

The formation in culture of dimethyl- and diethyl-nitrosamine from sodium nitrite and secondary amines was brought about by Streptococcus species, but not by members of several other genera tested. This formation appears to be non-enzymic, pH dependent, and may be catalyzed by one or more bacterial metabolic products.

Effect of Oxidized Myofibrils Protein Subjected to Mutiple Freeze-Thaw Cycles on N-Nitrosamine Formation in In Vitro Model System

2012 ◽  
Vol 550-553 ◽  
pp. 1590-1594 ◽  
Author(s):  
Hua Yang ◽  
Pei Pei Meng ◽  
Rui Wang ◽  
Pei Ran Li ◽  
Peng Li ◽  
...  
Keyword(s):  
Sodium Nitrite ◽  
Protein Carbonyl ◽  
Model System ◽  
Model Systems ◽  
Secondary Amines ◽  
Freeze Thaw ◽  
Heavy Chains ◽  
Carcinogenic Substance ◽  
The Times

N-nitrosamine is a kind of carcinogenic substance, which is possibly formed in the reaction of nitrites with amino acids or secondary amines. Two in vitro model systems were designed to evaluate the influence of oxidized myofibrils protein subjected to repeated freeze-thaw cycles (0, 1, 2, 3, 4, 7, 10 times) on N-nitrosamine formation. Model system I contains diethylamine and sodium nitrite, while model system II contains only sodium nitrite as reaction solution. Oxidized myofibrils protein were added to both systems. The results revealed that as the number of freeze-thaw cycles increased, cross-linking of myosin heavy chains and the content of protein carbonyl increased, but the content of protein sulfydryl decreased, which indicates oxidization of protein occurred. The concentration of N-nitrosodiethylamine increased as the number of freeze-thaw cycles increased, especially after four cycles. Oxidized myofibrils protein promoted the formation of N-nitrosodiethylamine. The more the times of freeze-thaw cycles were subjected, the more oxidization of myofibrils protein occurred and the higher yield of the N-nitrosodiethylamine.

ДИНИТРОЗИЛЬНЫЕ КОМПЛЕКСЫ ЖЕЛЕЗА C ТИОЛСОДЕРЖАЩИМИ ЛИГАНДАМИ ПРЕДСТАВЛЕНЫ В ЖИВЫХ ОРГАНИЗМАХ В ОСНОВНОМ ИХ БИЯДЕРНОЙ ФОРМОЙ

2020 ◽  
Vol 65 (6) ◽  
pp. 1142-1153
Author(s):  
В.Д. Микоян ◽  
◽  
Е.Н. Бургова ◽  
Р.Р. Бородулин ◽  
А.Ф. Ванин ◽  
...  
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Sodium Nitrite ◽  
Iron Complexes ◽  
Paramagnetic Resonance ◽  
First Case ◽  
Dinitrosyl Iron ◽  
Electron Paramagnetic ◽  
Dinitrosyl Complexes

The number of mononitrosyl iron complexes with diethyldithiocarbamate, formed in the liver of mice in vivo and in vitro after intraperitoneal injection of binuclear dinitrosyl iron complexes with N-acetyl-L-cysteine or glutathione, S-nitrosoglutathione, sodium nitrite or the vasodilating drug Isoket® was assessed by electron paramagnetic resonance (EPR). The number of the said complexes, in contrast to the complexes, formed after nitrite or Isoket administration, the level of which sharply increased after treatment of liver preparations with a strong reducing agent - dithionite, did not change in the presence of dithionite. It was concluded that, in the first case, EPR-detectable mononitrosyl iron complexes with diethyldithiocarbamate in the absence and presence of dithionite appeared as a result of the reaction of NO formed from nitrite with Fe2+-dieth- yldithiocarbamate and Fe3+-diethyldithiocarbamate complexes, respectively. In the second case, mononitrosyl iron complexes with diethyldithiocarbamate appeared as a result of the transition of iron-mononitosyl fragments from ready-made iron-dinitrosyl groups of binuclear dinitrosyl complexes, which is three to four times higher than the content of the mononuclear form of these complexes in the tissue...

Novel coumarin containing dithiocarbamate derivatives as potent α-glucosidase inhibitors for management of type 2 diabetes

2020 ◽  
Vol 16 ◽  
Author(s):  
Marjan Mollazadeh ◽  
Maryam Mohammadi-Khanaposhtani ◽  
Yousef Valizadeh ◽  
Afsaneh Zonouzi ◽  
Mohammad Ali Faramarzi ◽  
...  
Keyword(s):  
Type 2 Diabetes ◽  
Kinetic Study ◽  
Active Site ◽  
Docking Study ◽  
Secondary Amines ◽  
Molecular Docking Study ◽  
Glucosidase Inhibitors ◽  
Dithiocarbamate Derivatives

Background: α-Glucosidase is a hydrolyze enzyme that plays a crucial role in degradation of carbohydrates and starch to glucose. Hence, α-glucosidase is an important target in the carbohydrate mediated diseases such as diabetes mellitus. Objective: In this study, novel coumarin containing dithiocarbamate derivatives 4a-n were synthesized and evaluated against α-glucosidase in vitro and in silico. Methods: These compounds were obtained of reaction between 4-(bromomethyl)-7-methoxy-2H-chromen-2-one 1, carbon disulfide 2, and primary or secondary amines 3a-n in the presence potassium hydroxide and ethanol at room temperature. In vitro α-glucosidase inhibition and kinetic study of these compounds were performed. Furthermore, docking study of the most potent compounds was also performed by Auto Dock Tools (version 1.5.6). Results: Obtained results showed that all the synthesized compounds exhibited prominent inhibitory activities (IC50 = 85.0 ± 4.0-566.6 ± 8.6 μM) in comparison to acarbose as standard inhibitor (IC50 = 750.0 ± 9.0 µM). Among them, secondary amine derivative 4d with pendant indole group was the most potent inhibitor. Enzyme kinetic study of the compound 4d revealed that this compound compete with substrate to connect to the active site of α-glucosidase and therefore is a competitive inhibitor. Also, molecular docking study predicted that this compound as well interacted with α-glucosidase active site pocket. Conclusion: Our results suggest that the coumarin-dithiocarbamate scaffold can be a promising lead structure for design potent α-glucosidase inhibitors for treatment of type 2 diabetes.

scholarly journals Anti-TNF Alpha Antibody Humira with pH-dependent Binding Characteristics: A constant-pH Molecular Dynamics, Gaussian Accelerated Molecular Dynamics, and In Vitro Study

Biomolecules ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 334
Author(s):  
Shih-Ting Hong ◽  
Yu-Cheng Su ◽  
Yu-Jen Wang ◽  
Tian-Lu Cheng ◽  
Yeng-Tseng Wang
Keyword(s):  
Molecular Dynamics ◽  
Tnf Alpha ◽  
Complex Structures ◽  
Binding Characteristics ◽  
Accelerated Molecular Dynamics ◽  
Constant Ph ◽  
Ph Dependent ◽  
Constant Ph Molecular Dynamics ◽  
Antibody Drug

Humira is a monoclonal antibody that binds to TNF alpha, inactivates TNF alpha receptors, and inhibits inflammation. Neonatal Fc receptors can mediate the transcytosis of Humira–TNF alpha complex structures and process them toward degradation pathways, which reduces the therapeutic effect of Humira. Allowing the Humira–TNF alpha complex structures to dissociate to Humira and soluble TNF alpha in the early endosome to enable Humira recycling is crucial. We used the cytoplasmic pH (7.4), the early endosomal pH (6.0), and pKa of histidine side chains (6.0–6.4) to mutate the residues of complementarity-determining regions with histidine. Our engineered Humira (W1-Humira) can bind to TNF alpha in plasma at neutral pH and dissociate from the TNF alpha in the endosome at acidic pH. We used the constant-pH molecular dynamics, Gaussian accelerated molecular dynamics, two-dimensional potential mean force profiles, and in vitro methods to investigate the characteristics of W1-Humira. Our results revealed that the proposed Humira can bind TNF alpha with pH-dependent affinity in vitro. The W1-Humira was weaker than wild-type Humira at neutral pH in vitro, and our prediction results were close to the in vitro results. Furthermore, our approach displayed a high accuracy in antibody pH-dependent binding characteristics prediction, which may facilitate antibody drug design. Advancements in computational methods and computing power may further aid in addressing the challenges in antibody drug design.

scholarly journals pH-dependent binding of KDEL to its receptor in vitro.

1993 ◽  
Vol 268 (10) ◽  
pp. 7465-7468
Author(s):  
D.W. Wilson ◽  
M.J. Lewis ◽  
H.R. Pelham
Keyword(s):  
Ph Dependent

scholarly journals Cofilin is a pH sensor for actin free barbed end formation: role of phosphoinositide binding

2008 ◽  
Vol 183 (5) ◽  
pp. 865-879 ◽  
Author(s):  
Christian Frantz ◽  
Gabriela Barreiro ◽  
Laura Dominguez ◽  
Xiaoming Chen ◽  
Robert Eddy ◽  
...  
Keyword(s):  
Actin Filament ◽  
Structural Changes ◽  
Ph Sensor ◽  
Ph Sensitive ◽  
Actin Binding ◽  
Filamentous Actin ◽  
Filament Dynamics ◽  
Ph Dependent ◽  
Dynamics Simulations

Newly generated actin free barbed ends at the front of motile cells provide sites for actin filament assembly driving membrane protrusion. Growth factors induce a rapid biphasic increase in actin free barbed ends, and we found both phases absent in fibroblasts lacking H+ efflux by the Na-H exchanger NHE1. The first phase is restored by expression of mutant cofilin-H133A but not unphosphorylated cofilin-S3A. Constant pH molecular dynamics simulations and nuclear magnetic resonance (NMR) reveal pH-sensitive structural changes in the cofilin C-terminal filamentous actin binding site dependent on His133. However, cofilin-H133A retains pH-sensitive changes in NMR spectra and severing activity in vitro, which suggests that it has a more complex behavior in cells. Cofilin activity is inhibited by phosphoinositide binding, and we found that phosphoinositide binding is pH-dependent for wild-type cofilin, with decreased binding at a higher pH. In contrast, phosphoinositide binding by cofilin-H133A is attenuated and pH insensitive. These data suggest a molecular mechanism whereby cofilin acts as a pH sensor to mediate a pH-dependent actin filament dynamics.

scholarly journals Synthesis and Biological Evaluation of Aminonaphthols Incorporated Indole Derivatives

2014 ◽  
Vol 2014 ◽  
pp. 1-12 ◽  
Author(s):  
Saundane Anand Raghunath ◽  
Kirankumar Nandibeoor Mathada
Keyword(s):  
Radical Scavenging ◽  
Antitubercular Activity ◽  
Antimicrobial Activities ◽  
Biological Evaluation ◽  
Secondary Amines ◽  
Anticancer Activities ◽  
One Pot ◽  
Antioxidant Power ◽  
Mic Value

An efficient one pot condensation of naphthols (1), 2,5-disubstituted indole-3-carboxaldehydes (2), and secondary amines (3) has been achieved using dichloromethane as a solvent, stirring at room temperature. Some of the new [(disubstituted amino)(5-substituted 2-phenyl-1H-indol-3-yl)methyl]naphthalene-ols (4) derivatives were prepared in good yields. The significant features of this method are simple work-up procedure, inexpensive nontoxic solvent, shorter reaction times, and excellent product yields. The structures of newly synthesized compounds (4a–r) are confirmed by their elemental analysis, FTIR, 1H and 13C NMR, and mass spectral data. These compounds were screened for their in vitro antioxidant, antimicrobial, antitubercular, and anticancer activities. Among the synthesized compounds (4a–r), the compound 4e exhibited highest activity for radical scavenging and ferric ions reducing antioxidant power activities; compounds 4b, 4h, and 4k showed good metal chelating activity. Compounds 4n and 4q showed excellent antimicrobial activities with MIC value 08 µg/mL against tested strains. Compounds 4h, 4k, 4n, and 4q exhibited promising antitubercular activity with MIC value 12.5 µg/mL. Compounds 4k and 4q exhibited 100% cell lysis at concentration 10 µg/mL against MDA-MB-231 (human adenocarcinoma mammary gland) cell lines.

scholarly journals Metabolism and Pharmacokinetic Study of the Boron-Containing Prodrug of Belinostat (ZL277), a Pan HDAC Inhibitor with Enhanced Bioavailability

2019 ◽  
Vol 12 (4) ◽  
pp. 180 ◽  
Author(s):  
Changde Zhang ◽  
Shanchun Guo ◽  
Qiu Zhong ◽  
Qiang Zhang ◽  
Ahamed Hossain ◽  
...  
Keyword(s):  
Pharmacokinetic Study ◽  
Hdac Inhibitor ◽  
Active Drug ◽  
Hydrolysis Product ◽  
Liver Microsomes ◽  
Tumor Model ◽  
Maximum Plasma ◽  
Metabolic Products

ZL277 is a prodrug of belinostat with enhanced bioavailability and efficacy as a pan histone deacetylase (HDAC) inhibitor. In this study, we investigated the metabolism and pharmacokinetics of ZL277 in liver S9 fractions, liver microsomes, liver cytosol, and in mice. Metabolic products were identified and quantified by a combination of liquid chromatography and tandem mass spectrometry. The in vitro metabolic profile of ZL277 includes ZL277-B(OH)2-452, the major oxidative metabolite ZL277-OH-424, the active ingredient belinostat, belinostat amide, belinostat acid, and methylated belinostat in liver S9 fractions. Both ZL277-OH-424 and belinostat underwent further glucuronidation in liver microsome, whereas only ZL277-OH-424, but not belinostat, underwent some level of sulfation in rat liver cytosols. These metabolites were examined in plasma and in a breast tumor model in vivo. They were also examined in urine and feces from mice treated with ZL277. The pharmacokinetic study of ZL277 showed the parameters of active drug belinostat with a half-life (t1/2) of 10.7 h, an area under curve value (AUC) of 1506.9 ng/mL*h, and a maximum plasma concentration (Cmax) of 172 ng/mL, reached 3 h after a single dose of 10 mg/kg. The hydrolysis product of the prodrug, ZL277-B(OH)2-452 showed an AUC of 8306 ng/mL*h and Cmax of 931 ng/mL 3 h after drug administration.

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