N- and S-homocysteinylation reduce the binding of human serum albumin to catechins
- 268 Downloads
The dietary flavonoids epicatechin (EC), epigallocatechin (EGC), epicatechin gallate (ECG) and epigallocatechin gallate (EGCG) have been shown to interact with circulating albumin for transport in blood to different body tissues. This interaction may modulate their bioavailability and effectiveness.
Using affinity capillary electrophoresis to assess binding constants (K b), we investigated whether posttranslational modification of human serum albumin (HSA) through N- and S-homocysteinylation, commonly observed in hyperhomocysteinemia, may modify its interaction with catechins.
S-Hcy HSA had lower Kb values toward EC (14 %), EGC (18 %), ECG (24 %) and EGCG (30 %). Similarly, N-Hcy HSA had lower Kb values toward EC (17 %), EGC (22 %), ECG (23 %) and EGCG (32 %). No differences were observed in the affinity between catechins, albumin and mercaptalbumin.
Therefore, HSA posttranslational modifications typical of hyperhomocysteinemia reduce its affinity to catechins, potentially affecting their pharmacokinetics and availability at the active sites.
KeywordsAffinity capillary electrophoresis Catechins Albumin Binding constant
Affinity capillary electrophoresis
Human serum albumin
This research was supported by the Sardinia region within the framework of the L.R. n° 7 - 2007, call 2010, Grant n° CPR-25920 (Pintus) and the Bank of Sardinia Foundation (Pintus, Carru, Zinellu). We thank Dr. Maria Antonietta Meloni for manuscript proofreading.
Compliance with ethical standards
Conflict of interest
Authors declare that they have no competing financial, professional or personal interests that might have influenced the performance or presentation of the described work.
- 7.Henning SM, Choo JJ, Heber D (2008) Nongallated compared with gallated flavan-3-ols in green and black tea are more bioavailable. J Nutr 138:1529–1534Google Scholar
- 11.Peters T Jr (1996) All about albumin: biochemistry, genetics, and medical applications. Academic Press, San Diego, CA, pp 51–54Google Scholar
- 13.Jakubowski H (1997) Metabolism of homocysteine thiolactone in human cell cultures. Possible mechanism for pathological consequences of elevated homocysteine levels. J Biol Chem 272:1935–1942Google Scholar
- 15.Spahr PF, Edsall JT (1964) Amino acid composition of human and bovine serum mercaptalbumin. J Biol Chem 239:850–854Google Scholar
- 23.Jakubowski H (2000) Homocysteine thiolactone: metabolic origin and protein homocysteinylation in humans. J Nutr 130:377S–381SGoogle Scholar
- 26.Ishii T, Minoda K, Bae MJ, Mori T, Uekusa Y, Ichikawa T, Aihara Y, Furuta T, Wakimoto T, Kan T, Nakayama T (2010) Binding affinity of tea catechins for HSA: characterization by high-performance affinity chromatography with immobilized albumin column. Mol Nutr Food Res 54:816–822CrossRefGoogle Scholar
- 31.Chow HHS, Hakim IA, Vining DR, Crowell JA, Ranger-Moore J, Chew WM, Celaya CA, Rodney SR, Hara Y, Alberts DS (2005) Effects of dosing condition on the oral bioavailability of green tea catechins after single-dose administration of Polyphenon E in healthy individuals. Clin Cancer Res 11:4627–4633CrossRefGoogle Scholar