title: Voltammetric sensing of phosphoproteins using a gallium(III) acetylacetonate-modified carbon paste electrode.
abstract: The voltammetric detection of phosphoproteins was developed using a gallium(III) acetylacetonate-modified carbon paste electrode.  Because phosphate groups of the protein interacted with the gallium(III) ion, the protein was accumulated on the electrode surface.  A hexaammine ruthenium(III) ion, which combined with the functional groups, was used to monitor the interaction.  When phosvitin and hexaammine ruthenium(III) ions were incubated in 0.1 M acetate buffer (pH 3.2), a reduction peak of hexaammine ruthenium(III) ion at the electrode decreased as the concentration of the protein increased.  In contrast, an increase in the peak current was observed with a plain carbon paste electrode.  These results were caused by a competitive reaction of the phosphate groups with the hexaammine ruthenium(III) and gallium(III) ions.  In the presence of α-, β- and κ-caseins, the electrode response decreased due to the order of the numbers of phosphate groups.  This method could be applied to the sensing of phosphoproteins at the 10(-10) M level.
authors.affiliation: Maebashi Institute of Technology, Gunma, Japan. kzsuga@maebashi-it.ac.jp
authors.forename: Kazuharu
authors.initials: K
authors.lastname: Sugawara
authors.forename: Asako
authors.initials: A
authors.lastname: Yugami
authors.forename: Toshihiko
authors.initials: T
authors.lastname: Kadoya
mesh_terms: D000818:Animals; D002244:Carbon / Q000737:chemistry*; D002364:Caseins / Q000032:analysis / Q000737:chemistry; D002417:Cattle; D004563:Electrochemistry / Q000295:instrumentation / Q000379:methods*; D004566:Electrodes; D006885:Hydroxybutyrates / Q000737:chemistry*; D009824:Ointments; D010422:Pentanones / Q000737:chemistry*; D010710:Phosphates / Q000737:chemistry; D010750:Phosphoproteins / Q000032:analysis* / Q000737:chemistry; D010774:Phosvitin / Q000032:analysis / Q000737:chemistry; D017975:Ruthenium Compounds / Q000737:chemistry
chemical_list: D002364:Caseins; D006885:Hydroxybutyrates; D009824:Ointments; D010422:Pentanones; D010710:Phosphates; D010750:Phosphoproteins; D017975:Ruthenium Compounds; C049529:acetyl acetonate; C031584:hexammineruthenium; D002244:Carbon; D010774:Phosvitin