Identification of 3-Hydroxykynurenine and Xanthurenic Acid and Quantitation of 3-Hydroxykynurenine Transaminase Activity Using HPLC with Electrochemical Detection

Abstract

Identification of 3-hydroxykynurenine and xanthurenic acid and determination of 3-hydroxykynurenine transaminase activity using HPLC with electrochemical detection (HPLC-ED) are described using mosquito larval samples as testing materials. Results indicate that 3-hydroxykynurenine and xanthurenic acid in crude biological samples can be identified based on their electrochemical and chromatographic behaviors during HPLC-ED analysis. Xanthurenic acid is produced through transamination of 3-hydroxykynurenine, and identification of xanthurenic acid in the mosquito larval extract also leads to the detection of 3-hydroxykynurenine transaminase activity in this insect species.

Using the same HPLC-ED technique, a method to detect and quantitate 3-hydroxykynurenine transaminase activity is developed using isolated mosquito larval protein as enzyme source, and the applicability of the HPLC-ED transaminase assay for samples from other resources is demonstrated using supernatant of mouse liver and kidney homogenates.