title: N- and S-homocysteinylation reduce the binding of human serum albumin to catechins.
abstract: OBJECTIVE
  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.
  
  
  METHODS
  Using affinity capillary electrophoresis to assess binding constants (Kb), 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.
  
  
  RESULTS
  S-Hcy HSA had lower Kbvalues toward EC (14 %), EGC (18 %), ECG (24 %) and EGCG (30 %). Similarly, N-Hcy HSA had lower Kbvalues toward EC (17 %), EGC (22 %), ECG (23 %) and EGCG (32 %). No differences were observed in the affinity between catechins, albumin and mercaptalbumin.
  
  
  CONCLUSIONS
  Therefore, HSA posttranslational modifications typical of hyperhomocysteinemia reduce its affinity to catechins, potentially affecting their pharmacokinetics and availability at the active sites.
authors.affiliation: Department of Biomedical Sciences, University of Sassari, Viale San Pietro 43/B, 07100, Sassari, Italy. azinellu@uniss.it.
authors.forename: Angelo
authors.initials: A
authors.lastname: Zinellu
authors.affiliation: Department of Biomedical Sciences, University of Sassari, Viale San Pietro 43/B, 07100, Sassari, Italy.
authors.forename: Salvatore
authors.initials: S
authors.lastname: Sotgia
authors.affiliation: Department of Biomedical Sciences, University of Sassari, Viale San Pietro 43/B, 07100, Sassari, Italy.
authors.forename: Bastianina
authors.initials: B
authors.lastname: Scanu
authors.affiliation: Department of Biomedical Sciences, University of Sassari, Viale San Pietro 43/B, 07100, Sassari, Italy.
authors.forename: Dionigia
authors.initials: D
authors.lastname: Arru
authors.affiliation: Department of Biomedical Sciences, University of Sassari, Viale San Pietro 43/B, 07100, Sassari, Italy.
authors.forename: Annalisa
authors.initials: A
authors.lastname: Cossu
authors.affiliation: Department of Biomedical Sciences, University of Sassari, Viale San Pietro 43/B, 07100, Sassari, Italy.
authors.forename: Anna Maria
authors.initials: AM
authors.lastname: Posadino
authors.affiliation: Department of Biomedical Sciences, University of Sassari, Viale San Pietro 43/B, 07100, Sassari, Italy.
authors.forename: Roberta
authors.initials: R
authors.lastname: Giordo
authors.affiliation: Department of Clinical Pharmacology, School of Medicine, Flinders University, Adelaide, Australia.
authors.forename: Arduino A
authors.initials: AA
authors.lastname: Mangoni
authors.affiliation: Department of Biomedical Sciences, University of Sassari, Viale San Pietro 43/B, 07100, Sassari, Italy.
authors.forename: Gianfranco
authors.initials: G
authors.lastname: Pintus
authors.affiliation: Department of Biomedical Sciences, University of Sassari, Viale San Pietro 43/B, 07100, Sassari, Italy. carru@uniss.it.
authors.forename: Ciriaco
authors.initials: C
authors.lastname: Carru
mesh_terms: D049148:Aminoacylation; D002392:Catechin / Q000031:analogs & derivatives / Q000378:metabolism*; D003545:Cysteine / Q000378:metabolism; D019075:Electrophoresis, Capillary; D006710:Homocysteine / Q000031:analogs & derivatives / Q000378:metabolism*; D006801:Humans; D020138:Hyperhomocysteinemia / Q000097:blood / Q000378:metabolism; D007700:Kinetics; D008024:Ligands; D008239:Lysine / Q000378:metabolism; D011499:Protein Processing, Post-Translational; D012709:Serum Albumin / Q000378:metabolism*; D000075462:Serum Albumin, Human
chemical_list: C422455:ALB protein, human; D008024:Ligands; D012709:Serum Albumin; C001702:mercaptoalbumin; D006710:Homocysteine; D002392:Catechin; C062669:epicatechin gallate; C045651:epigallocatechin gallate; C007957:homocysteine thiolactone; C057580:gallocatechol; D008239:Lysine; D003545:Cysteine; D000075462:Serum Albumin, Human
keywords: Affinity capillary electrophoresis; Albumin; Binding constant; Catechins