N- and S-homocysteinylation reduce the binding of human serum albumin to catechins
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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.
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