title: Evaluation of human and bovine serum albumin on oxidation characteristics by a photosensitization reaction under complete binding of talaporfin sodium.
abstract: BACKGROUND
  In order to investigate the therapeutic interaction of an extra-cellular photosensitization reaction, we evaluated the oxidation characteristics of human and bovine serum albumin by this reaction with talaporfin sodium under complete binding with albumin by spectroscopic analysis in a cell-free solution.
  
  
  METHODS
  The solution was composed of 20μg/ml talaporfin sodium and 2.1mg/ml human or bovine serum albumin. A 662nm laser light was used to irradiate the solution. Visible absorbance spectra of solutions were measured to obtain the oxidized and non-oxidized relative densities of albumin and talaporfin sodium before and after the photosensitization reaction. The defined oxidation path ratio of talaporfin sodium to albumin reflected the oxidation of the solution. Absorbance wavelengths at approximately 240 and 660nm were used to calculate normalized molecular densities of oxidized albumin and talaporfin sodium, respectively.
  
  
  CONCLUSIONS
  The oxidation path ratio of talaporfin sodium to albumin when binding human serum albumin was approximately 1.8 times larger than that of bovine serum albumin during the photosensitization reaction from 1 to 50J/cm(2). We hypothesized that the oxidation path ratio results might have been caused by talaporfin sodium binding affinity or binding location difference between the two albumins, because the fluorescence lifetimes of talaporfin sodium bound to human and bovine serum albumin were 7.0 and 4.9ns, respectively. Therefore, the photodynamic therapeutic interaction might be stronger with human serum albumin than with bovine serum albumin in the case of extracellular photosensitization reaction.
authors.affiliation: Graduate School of Science and Technology, Keio University, 3-14-1, Hiyoshi, Kohoku-ku, Yokohama City, Kanagawa 223-8522, Japan. Electronic address: m.kurotsu@arai.appi.keio.ac.jp.
authors.forename: Mariko
authors.initials: M
authors.lastname: Kurotsu
authors.affiliation: School of Fundamental Science and Technology, Keio University, 3-14-1, Hiyoshi, Kohoku-ku, Yokohama City, Kanagawa 223-8522, Japan. Electronic address: m.yajima@arai.appi.keio.ac.jp.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Yajima
authors.affiliation: School of Fundamental Science and Technology, Keio University, 3-14-1, Hiyoshi, Kohoku-ku, Yokohama City, Kanagawa 223-8522, Japan. Electronic address: m.takahashi@arai.appi.keio.ac.jp.
authors.forename: Mei
authors.initials: M
authors.lastname: Takahashi
authors.affiliation: School of Fundamental Science and Technology, Keio University, 3-14-1, Hiyoshi, Kohoku-ku, Yokohama City, Kanagawa 223-8522, Japan. Electronic address: e.ogawa@arai.appi.kei.ac.jp.
authors.forename: Emiyu
authors.initials: E
authors.lastname: Ogawa
authors.affiliation: School of Fundamental Science and Technology, Keio University, 3-14-1, Hiyoshi, Kohoku-ku, Yokohama City, Kanagawa 223-8522, Japan. Electronic address: tsunearai@appi.keio.ac.jp.
authors.forename: Tsunenori
authors.initials: T
authors.lastname: Arai
mesh_terms: D006801:Humans; D010084:Oxidation-Reduction; D010778:Photochemotherapy / Q000379:methods*; D017319:Photosensitizing Agents / Q000378:metabolism*; D011166:Porphyrins / Q000378:metabolism*; D011485:Protein Binding; D012709:Serum Albumin / Q000378:metabolism*; D012710:Serum Albumin, Bovine / Q000378:metabolism; D013050:Spectrometry, Fluorescence
chemical_list: D017319:Photosensitizing Agents; D011166:Porphyrins; D012709:Serum Albumin; D012710:Serum Albumin, Bovine; C053434:Talaporfin
keywords: Bovine serum albumin; Extra-cellular photosensitization reaction; Human serum albumin; Oxidation characteristics; Talaporfin sodium; Therapeutic interaction