title: Investigation on potential enzyme toxicity of clenbuterol to trypsin.
abstract: Clenbuterol (CLB) is a kind of β2-adrenergic agonists which was illegally used as feed additives nowadays. The toxic interaction of CLB with trypsin, an important digestive enzyme, was studied in vitro using multi-spectroscopic methods and molecular modeling methods. CLB was proved to bind with trypsin in S1 pocket, forming a complex driven by the dominant force of H-bond. The binding constant was calculated to be 1.79887×10(5) L mol(-1) at 289 K and 0.32584×10(5) L mol(-1) at 310 K, respectively. The skeleton of trypsin became loosened and unfolded with the amino residues microenvironment changed. The secondary and tertiary structure of trypsin also varied. Molecular modeling studies illustrated specific display of the binding information and explained most of the experiment phenomena. The binding site of CLB induced the fluorescence quenching as well as inhibition of enzyme activity of trypsin. The study confirmed that CLB had potential toxicity on both the structure and function of trypsin and the effects enhanced with the increasing concentration of CLB.
authors: Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Jinan 250100, PR China.
authors: Jun
authors: J
authors: Chai
authors: Qifei
authors: Q
authors: Xu
authors: Jinping
authors: J
authors: Dai
authors: Rutao
authors: R
authors: Liu
mesh_terms: D000318:Adrenergic beta-Agonists / Q000633:toxicity*; D000818:Animals; D002417:Cattle; D002942:Circular Dichroism; D002976:Clenbuterol / Q000633:toxicity*; D008958:Models, Molecular; D011487:Protein Conformation / Q000187:drug effects; D058767:Protein Unfolding / Q000187:drug effects; D013050:Spectrometry, Fluorescence; D013056:Spectrophotometry, Ultraviolet; D013816:Thermodynamics; D014357:Trypsin / Q000737:chemistry / Q000378:metabolism*
chemical_list: D000318:Adrenergic beta-Agonists; D014357:Trypsin; D002976:Clenbuterol