The Oxidative Activity of Ellagitannins Dictates Their Tendency To Form Highly Stabilized Complexes with Bovine Serum Albumin at Increased pH.
Many food and forage plants contain tannins, high molecular weight polyphenols that characteristically interact strongly with protein, forming complexes that affect taste, nutritional quality, and the health of the consumer. In the present study, the interaction between bovine serum albumin (BSA) and each of seven hydrolyzable tannins or epigallocatechin gallate was examined. The objective was to define the effect of tannin oxidation, measured as oxidative activity (browning) or as oxidizability (degradation monitored by HPLC), on the formation on highly stabilized tannin-protein complexes and to determine how the reaction depended on the pH conditions. Gel electrophoresis and MALDI-TOF-MS were used to assess the formation of tannin-protein complexes. The results showed that tannin oxidizability was directly correlated with the tendency of the tannins to form highly stabilized complexes with BSA at increased pH (7.6). However, at slightly lower pH (6.7), other tannin features, such as the size and flexibility of the tannin, appeared to dictate the formation of highly stabilized tannin-protein complexes.
Department of Chemistry, Laboratory of Organic Chemistry and Chemical Biology, University of Turku , FI-20014 Turku, Finland.
Marica T
MT
Engström
Department of Chemistry and Biochemistry, Miami University , Oxford, Ohio 45056, United States.
Xiaowei
X
Sun
Department of Chemistry and Biochemistry, Miami University , Oxford, Ohio 45056, United States.
Matthew P
MP
Suber
Department of Chemistry and Biochemistry, Miami University , Oxford, Ohio 45056, United States.
Min
M
Li
Department of Chemistry, Laboratory of Organic Chemistry and Chemical Biology, University of Turku , FI-20014 Turku, Finland.
Juha-Pekka
JP
Salminen
Department of Chemistry and Biochemistry, Miami University , Oxford, Ohio 45056, United States.
Ann E
AE
Hagerman
D000975:Antioxidants / Q000737:chemistry; D002392:Catechin / Q000031:analogs & derivatives / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D047348:Hydrolyzable Tannins / Q000737:chemistry*; D008970:Molecular Weight; D010084:Oxidation-Reduction; D059808:Polyphenols / Q000737:chemistry; D011487:Protein Conformation; D012710:Serum Albumin, Bovine / Q000737:chemistry*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
D000975:Antioxidants; D047348:Hydrolyzable Tannins; D059808:Polyphenols; D012710:Serum Albumin, Bovine; D002392:Catechin; C045651:epigallocatechin gallate
MALDI-TOF-MS; gel electrophoresis; oxidative activity; pH; protein; tannin