Analytical Sciences

Abstract − Analytical Sciences, 22(8), 1139 (2006).

Determination of Fructosyl Amino Acids and Fructosyl Peptides in Protease-digested Blood Sample by a Flow-Injection System with an Enzyme Reactor
Yoko NANJO,*,** Ryuzo HAYASHI,* and Toshio YAO**
*Oji Scientific Instruments Co., Ltd., 4-3-1 Jokoji, Amagasaki, Hyogo 660-0811, Japan
**Department of Applied Chemistry, Graduate School of Engineering, Osaka Prefecture University, 1-1 Gakuencho, Naka, Sakai, Osaka 599-8531, Japan
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 × 10-6 to 5.8 × 10-4 M. The present method could be successfully applied to the assay of FV and FVH in the protease-digested blood samples.