title: Investigation Into Efficiency of a Novel Glycol Chitosan-Bestatin Conjugate to Protect Thymopoietin Oligopeptides From Enzymatic Degradation.
abstract: In this study, a novel glycol chitosan (GCS)-bestatin conjugate was synthesized and evaluated to demonstrate its efficacy in protecting thymopoietin oligopeptides from aminopeptidase-mediated degradation. Moreover, the mechanism and relative susceptibility of three thymopoietin oligopeptides, thymocartin (TP4), thymopentin (TP5), and thymotrinan (TP3), to enzymatic degradation were investigated and compared at the molecular level. Initial investigations indicated that formation of the GCS-bestatin conjugate, with a substitution degree of 7.0% (moles of bestatin per mole of glycol glucosamine unit), could significantly protect all 3 peptides from aminopeptidase-mediated degradation in a concentration-dependent manner. The space hindrance and loss of one pair of hydrogen bonds, resulting from the covalent conjugation of chitosan with bestatin, did not affect the specific interaction between bestatin and aminopeptidase. Moreover, TP4 displayed a higher degradation clearance compared with those of TP5 and TP3 under the same experimental conditions. The varying levels of susceptibility of these 3 peptides to aminopeptidase (TP4 > TP5 > TP3) were closely related to differences in their binding energies to enzyme, which mainly involved Van der Waals forces and electrostatic interactions, as supported by the results of molecular dynamics simulations. These results suggest that GCS-bestatin conjugate might be useful in the delivery of thymopoietin oligopeptides by mucosal routes, and that TP3 and TP5 are better alternatives to TP4 for delivery because of their robust resistance against enzymatic degradation.
authors.affiliation: National Engineering Laboratory for AIDS Vaccine, School of Life Sciences, Jilin University, Changchun 130012, China; Key Laboratory for Molecular Enzymology and Engineering the Ministry of Education, School of Life Sciences, Jilin University, Changchun 130012, China; State Key Laboratory of New Pharmaceutical Preparations and Excipients, China Shijiazhuang Pharmaceutical Group Co., Ltd., Shijiazhuang 050051, China. Electronic address: zhangyongking1@gmail.com.
authors.forename: Yong
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: National Engineering Laboratory for AIDS Vaccine, School of Life Sciences, Jilin University, Changchun 130012, China.
authors.forename: Jiao
authors.initials: J
authors.lastname: Feng
authors.affiliation: School of Pharmacy, Shenyang Pharmaceutical University, Shenyang 110016, China.
authors.forename: Lili
authors.initials: L
authors.lastname: Cui
authors.affiliation: State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China.
authors.forename: Yuebin
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Key Laboratory for Molecular Enzymology and Engineering the Ministry of Education, School of Life Sciences, Jilin University, Changchun 130012, China.
authors.forename: Wenzhao
authors.initials: W
authors.lastname: Li
authors.affiliation: State Key Laboratory of New Pharmaceutical Preparations and Excipients, China Shijiazhuang Pharmaceutical Group Co., Ltd., Shijiazhuang 050051, China.
authors.forename: Chunlei
authors.initials: C
authors.lastname: Li
authors.affiliation: Key Laboratory for Molecular Enzymology and Engineering the Ministry of Education, School of Life Sciences, Jilin University, Changchun 130012, China; Department of Pharmaceutics, School of Pharmacy, Jilin Medical College, Jilin 132013, China.
authors.forename: Nianqiu
authors.initials: N
authors.lastname: Shi
authors.affiliation: National Engineering Laboratory for AIDS Vaccine, School of Life Sciences, Jilin University, Changchun 130012, China; Key Laboratory for Molecular Enzymology and Engineering the Ministry of Education, School of Life Sciences, Jilin University, Changchun 130012, China. Electronic address: chen_yan@jlu.edu.cn.
authors.forename: Yan
authors.initials: Y
authors.lastname: Chen
authors.affiliation: National Engineering Laboratory for AIDS Vaccine, School of Life Sciences, Jilin University, Changchun 130012, China; Key Laboratory for Molecular Enzymology and Engineering the Ministry of Education, School of Life Sciences, Jilin University, Changchun 130012, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Kong
mesh_terms: D000626:Aminopeptidases / Q000378:metabolism*; D048271:Chitosan / Q000737:chemistry / Q000378:metabolism*; D007930:Leucine / Q000031:analogs & derivatives* / Q000737:chemistry / Q000378:metabolism; D062105:Molecular Docking Simulation / Q000379:methods; D019906:Nuclear Magnetic Resonance, Biomolecular / Q000379:methods; D009842:Oligopeptides / Q000737:chemistry / Q000378:metabolism*; D020011:Protective Agents / Q000737:chemistry / Q000378:metabolism; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods; D013946:Thymopoietins / Q000737:chemistry / Q000378:metabolism*
chemical_list: D009842:Oligopeptides; D020011:Protective Agents; D013946:Thymopoietins; C118638:glycol-chitosan; D048271:Chitosan; D000626:Aminopeptidases; D007930:Leucine; C012211:ubenimex
keywords: aminopeptidase; chitosan; clearance; conjugation; degradation; inhibitor; kinetics; peptide; thymopoietin oligopeptides