title: Controlling the taste receptor accessible structure of rebaudioside A via binding to bovine serum albumin.
abstract: We illustrate a method that uses bovine serum albumin (BSA) to control the receptor-accessible part of rebaudioside A (Reb A). The critical micelle concentration (CMC) of Reb A was found to be 4.5 mM and 5 mM at pH 3 and 6.7 respectively. NMR studies show that below its CMC, Reb A binds weakly to BSA to generate a Reb A-protein complex ("RPC"), which is only modestly stable under varying conditions of pH (3.0-6.7) and temperature (4-40°C) with its binding affinities determined to be in the range of 5-280 mM. Furthermore, saturation transfer difference (STD) NMR experiments confirm that the RPC has fast exchange of the bitterness-instigating diterpene of Reb A into the binding sites of BSA. Our method can be used to alter the strength of Reb A-receptor interaction, as a result of binding of Reb A to BSA, which may ultimately lead to moderation of its taste.
authors.affiliation: Institute of Food Science, Cornell University, Ithaca, NY 14853-7201, USA. Electronic address: sm2295@cornell.edu.
authors.forename: Samriddh
authors.initials: S
authors.lastname: Mudgal
authors.affiliation: Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, NY 14853-1301, USA.
authors.forename: Ivan
authors.initials: I
authors.lastname: Keresztes
authors.affiliation: Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA.
authors.forename: Gerald W
authors.initials: GW
authors.lastname: Feigenson
authors.affiliation: Institute of Food Science, Cornell University, Ithaca, NY 14853-7201, USA.
authors.forename: S S H
authors.initials: SS
authors.lastname: Rizvi
mesh_terms: D001665:Binding Sites; D045786:Diterpenes, Kaurane / Q000737:chemistry*; D005503:Food Additives / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008962:Models, Theoretical; D011485:Protein Binding; D012710:Serum Albumin, Bovine / Q000737:chemistry*; D013549:Sweetening Agents / Q000737:chemistry*; D013649:Taste; D055697:Taste Perception; D013696:Temperature
chemical_list: D045786:Diterpenes, Kaurane; D005503:Food Additives; D013549:Sweetening Agents; D012710:Serum Albumin, Bovine; C025474:rebaudioside A
keywords: High intensity sweetener; Saturation transfer difference NMR; Stevia bitter inhibitor; Taste modifier