Transamination of 3-hydroxykynurenine to produce xanthurenic acid: a major branch pathway of tryptophan metabolism in the mosquito, Aedes aegypti, during larval development

Abstract

An electrochemically active compound was detected in the larvae of Aedes aegypti mosquitoes and progressive accumulation of this compound was observed during larval development. The compound was purified from mosquito larvae using various chromatographic techniques and spectral analysis of the purified compound resulted in its identification as xanthurenic acid. Production of xanthurenic acid results from the transamination of 3-hydroxykynuorenine, and analysis of the biochemical pathway in xanthurenic acid production revealed the presence of a particular transaminase that has a much higher specific activity to 3-hydroxykynurenine than to kynurenine in the mosquito larvae. Concentration of xanthurenic acid is closely related to the level of this transaminase activity. Results suggest that this particular transaminase plays an important role in regulating the level of 3-hydroxykynurenine in the mosquito, A. aegypti during larval development.