TRANSAMINATION OF 3-HYDROXYKYNURENINE TO PRODUCE XANTHURENIC ACID - AMAJOR BRANCH PATHWAY OF TRYPTOPHAN-METABOLISM IN THE MOSQUITO, AEDES-AEGYPTI, DURING LARVAL DEVELOPMENT

An electrochemically active compound was detected in the larvae of Aed es aegypti mosquitoes and progressive accumulation of this compound wa s observed during larval development. The compound was purified from m osquito larvae using various chromatographic techniques and spectral a nalysis of the purified compound resulted in its identification as xan thurenic acid. Production of xanthurenic acid results from the transam ination of 3-hydroxykynuorenine, and analysis of the biochemical pathw ay in xanthurenic acid production revealed the presence of a particula r transaminase that has a much higher specific activity to 3-hydroxyky nurenine than to kynurenine in the mosquito larvae. Concentration of x anthurenic acid is closely related to the level of this transaminase a ctivity. Results suggest that this particular transaminase plays an im portant role in regulating the level of 3-hydroxykynurenine in the mos quito, A. aegypti during larval development. (C) 1997 Elsevier Science Ltd. All rights reserved.