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Báo cáo khoa học: Peptides from purified soybean b-conglycinin inhibit fatty acid synthase by interaction with the thioesterase catalytic domain

Fatty acid synthase (FAS) is uniquely expressed at high levels in cancer cells and adipose tissue. The objectives of this study were to identify, purify and validate soy FAS inhibitory peptides and to predict their binding modes. Soy peptides were isolated from hydrolysates of purifiedb-conglyci-nin by co-immunoprecipitation and identified using LC-MS⁄MS. | ỊFEBS Journal Peptides from purified soybean p-conglycinin inhibit fatty acid synthase by interaction with the thioesterase catalytic domain Cristina Martinez-Villaluenga1 Sanjeewa G. Rupasinghe2 Mary A. Schuler2 and Elvira Gonzalez de Mejia1 1 Department of Food Science and Human Nutrition University of Illinois at Urbana-Champaign IL USA 2 Department of Celland DevelopmentalBiology University of Illinois at Urbana-Champaign IL USA Keywords b-conglycinin-derived peptides fatty acid synthase inhibitors soybean thioesterase Correspondence E. Gonzalez de Mejia 1201 West Gregory Drive 228 ERML MC-051 Urbana IL 61801 USA Fax 1 217 265 0925 Tel 1 217 244 3196 E-mail edemejia@illinois.edu Received 19 August 2009 revised 7 January 2010 accepted 8 January 2010 doi 10.1111 j.1742-4658.2010.07577.x Fatty acid synthase FAS is uniquely expressed at high levels in cancer cells and adipose tissue. The objectives of this study were to identify purify and validate soy FAS inhibitory peptides and to predict their binding modes. Soy peptides were isolated from hydrolysates of purified b-conglyci-nin by co-immunoprecipitation and identified using LC-MS MS. Three peptides KNPQLR EiTpEKNPQLR and RKQEeDeDEEQQRE inhibited FAS. The biological activity of these peptides was confirmed by their inhibitory activity against purified chicken FAS IC50 79 27 and 16 pM respectively and a high correlation r -0.7 with lipid accumulation in 3T3-L1 adipocytes. The FAS inhibitory potency of soy peptides also correlated with their molecular mass pl value and the number of negatively charged and hydrophilic residues. Molecular modeling predicted that the large FAS inhibitory peptides EITPEKNPQLR and RKQEEDE-DEEQQRE bond to the thioesterase domain of human FAS with lower interaction energies -442 and -353 kcal-mol-1 respectively than classical thioesterase inhibitors Orlistat -91 kcal-mol-1 and C75 -51 kcal-mol-1 . Docking studies suggested that soy peptides blocked the active site through interactions .