title: Determination of fructosyl amino acids and fructosyl peptides in protease-digested blood sample by a flow-injection system with an enzyme reactor.
abstract: A flow-injection system with an enzyme reactor was proposed for the measurement of fructosyl amino acids and fructosyl peptides in protease-digested blood samples. A fructosyl-amino acid oxidase (FAOX-TE) and two fructosyl-peptide oxidases (FPOX-CE and FPOX-CET) were covalently immobilized onto an inert support. They were used as the enzyme reactor in a FIA system with a hydrogen peroxide electrode. In particular, the FPOX-CET reactor possessed high selectivity for the detection of fructosyl valine (FV) and fructosyl valyl histidine (FVH) and an excellent operational stability. The proposed FIA system with the FPOX-CET reactor responded linearly to the concentration of FV over the dynamic range of 7.8 x 10(-6) to 5.8 x 10(-4) M. The present method could be successfully applied to the assay of FV and FVH in the protease-digested blood samples.
authors.affiliation: Oji Scientific Instruments Co., Ltd., Amagasaki, Hyogo, Japan.
authors.forename: Yoko
authors.initials: Y
authors.lastname: Nanjo
authors.forename: Ryuzo
authors.initials: R
authors.lastname: Hayashi
authors.forename: Toshio
authors.initials: T
authors.lastname: Yao
mesh_terms: D000596:Amino Acids / Q000032:analysis*; D001774:Blood Chemical Analysis / Q000379:methods; D004563:Electrochemistry / Q000295:instrumentation / Q000379:methods; D004566:Electrodes; D004800:Enzymes, Immobilized / Q000032:analysis; D005632:Fructose / Q000032:analysis* / Q000737:chemistry; D006639:Histidine / Q000737:chemistry; D006801:Humans; D006861:Hydrogen Peroxide / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D010447:Peptide Hydrolases / Q000737:chemistry / Q000378:metabolism; D010455:Peptides / Q000032:analysis* / Q000737:chemistry; D013379:Substrate Specificity; D013997:Time Factors; D014633:Valine / Q000737:chemistry
chemical_list: D000596:Amino Acids; D004800:Enzymes, Immobilized; D010455:Peptides; D005632:Fructose; D006639:Histidine; D006861:Hydrogen Peroxide; D010447:Peptide Hydrolases; D014633:Valine