Investigation on potential enzyme toxicity of clenbuterol to trypsin

Chai, Jinghua; Xu, Qifei; Dai, Jian; Liu, Rutao

doi:10.1016/j.saa.2012.12.017

Cited by 36 publications

(20 citation statements)

References 39 publications

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“…The β-sheet content decreased accompanied by a slight increase of α-helix and β-turn content, while the random coil content remained virtually unchanged. These results indicate that the addition of α-tocopherol induces changes in the natural secondary structure of trypsin/pepsin, which may lead to changes in the physiological function of trypsin/pepsin, such as enzyme activity [38][39][40].…”

Section: Spectroscopic Studiesmentioning

confidence: 86%

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Probing the binding mechanisms of α-tocopherol to trypsin and pepsin using isothermal titration calorimetry, spectroscopic, and molecular modeling methods

2016

J Biol Phys

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α-Tocopherol is a required nutrient for a variety of biological functions. In this study, the binding of α-tocopherol to trypsin and pepsin was investigated using isothermal titration calorimetry (ITC), steady-state and time-resolved fluorescence measurements, circular dichroism (CD) spectroscopy, and molecular modeling methods. Thermodynamic investigations reveal that α-tocopherol binds to trypsin/pepsin is synergistically driven by enthalpy and entropy. The fluorescence experimental results indicate that α-tocopherol can quench the fluorescence of trypsin/pepsin through a static quenching mechanism. The binding ability of α-tocopherol with trypsin/pepsin is in the intermediate range, and one molecule of α-tocopherol combines with one molecule of trypsin/pepsin. As shown by circular dichroism (CD) spectroscopy, α-tocopherol may induce conformational changes of trypsin/pepsin. Molecular modeling displays the specific binding site and gives information about binding forces and α-tocopherol-tryptophan (Trp)/tyrosine (Tyr) distances. In addition, the inhibition rate of α-tocopherol on trypsin and pepsin was studied. The study provides a basic data set for clarifying the binding mechanisms of α-tocopherol with trypsin and pepsin and is helpful for understanding its biological activity in vivo.

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Section: Spectroscopic Studiesmentioning

confidence: 86%

“…Far-UV CD spectra (260-200 nm) are used to determine the secondary structure of a protein. The characteristic CD bands reflect the content of the secondary structure, such as α-helices, β-sheets, β-turns and random coils [38]. The CD spectra of trypsin/pepsin in the absence and presence of α-tocopherol are shown in Fig.…”

Section: Spectroscopic Studiesmentioning

confidence: 99%

Probing the binding mechanisms of α-tocopherol to trypsin and pepsin using isothermal titration calorimetry, spectroscopic, and molecular modeling methods

2016

J Biol Phys

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“…The contents of β-sheet and random coil decreased, accompanied by an increase of α-helix and β-turn. These results indicate that the addition of glutathione/melatonin induces the changes of the natural secondary structure of pepsin, which may lead to changes of the physiological function of pepsin, such as the enzyme activity (Chai et al 2013;Chi et al 2010;Mu et al 2011). …”

Section: Spectroscopic Studiesmentioning

confidence: 82%

Binding of glutathione and melatonin to pepsin occurs via different binding mechanisms

2015

Eur Biophys J

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Glutathione is a hydrophilic antioxidant and melatonin is a hydrophobic antioxidant, thus, the binding mechanism of the two antioxidants interacting with protease may be different. In this study, binding of glutathione and melatonin to pepsin has been studied using isothermal titration calorimetry (ITC), equilibrium microdialysis, UV-Vis absorption spectroscopy, circular dichroism (CD) spectroscopy, and molecular modeling. Thermodynamic investigations reveal that the binding of glutathione/melatonin to pepsin is driven by favorable enthalpy and unfavorable entropy, and the major driving forces are hydrogen bond and van der Waals force. ITC, equilibrium microdialysis, and molecular modeling reveal that the binding of glutathione to pepsin is characterized by a high number of binding sites. For melatonin, one molecule of melatonin combines with one molecule of pepsin. These results confirm that glutathione/melatonin interact with pepsin through two different binding mechanisms. In addition, the UV-Vis absorption and CD experiments indicate that glutathione and melatonin may induce conformational and microenvironmental changes of pepsin. The conformational changes of pepsin may affect its biological function as protease.

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“…Although, it is obvious that this compound is in massive use (legal or illegal), little data concerning its toxicity and mutagenic/ genotoxic potential are available. Several studies (Chai et al, 2013;Lara-Pezzi et al, 2009;Mazzanti et al, 2007) revealed that clenbuterol exhibited toxicity on trypsin in an in vitro system and stimulated guinea pig heart rate. There is evidence about its influence on the cardiovascular system (cases such as tachycardia and hypertension) recorded by Mazzanti et al (2007) and Bilkoo et al (2007), as well as its significant impact on liver function in female pigs (Gojmerac et al, 2002).…”

Section: Resultsmentioning

confidence: 99%

Mutagenicity and DNA-damaging potential of clenbuterol and its metabolite 4-amino-3,5-dichlorobenzoic acid in vitro

Vulić

Durgo

Pleadin

et al. 2015

Food and Chemical Toxicology

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Investigation on potential enzyme toxicity of clenbuterol to trypsin

Cited by 36 publications

References 39 publications

Probing the binding mechanisms of α-tocopherol to trypsin and pepsin using isothermal titration calorimetry, spectroscopic, and molecular modeling methods

Probing the binding mechanisms of α-tocopherol to trypsin and pepsin using isothermal titration calorimetry, spectroscopic, and molecular modeling methods

Binding of glutathione and melatonin to pepsin occurs via different binding mechanisms

Mutagenicity and DNA-damaging potential of clenbuterol and its metabolite 4-amino-3,5-dichlorobenzoic acid in vitro

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