Cysteine and keto acids modulate mosquito kynurenine aminotransferase catalyzed kynurenic acid production

FEBS Lett. 2004 Nov 19;577(3):381-5. doi: 10.1016/j.febslet.2004.09.088.


Kynurenine aminotransferase (KAT) catalyzes the formation of kynurenic acid (KYNA), the natural antagonist of ionotropic glutamate receptors. This study tests potential substrates and assesses the effects of amino acids and keto acids on the activity of mosquito KAT. Various keto acids, when simultaneously present in the same reaction mixture, display a combined effect on KAT catalyzed KYNA production. Moreover, methionine and glutamine show inhibitory effects on KAT activity, while cysteine functions as either an antagonist or an inhibitor depending on the concentration. Therefore, the overall level of keto acids and cysteine might modulate the KYNA synthesis. Results from this study will be useful in the study of KAT regulation in other animals.

Publication types

  • Comparative Study
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Baculoviridae / genetics
  • Catalysis
  • Cells, Cultured
  • Culicidae / cytology
  • Culicidae / metabolism*
  • Cysteine / pharmacology*
  • Dose-Response Relationship, Drug
  • Keto Acids / pharmacology*
  • Kinetics
  • Kynurenic Acid / antagonists & inhibitors*
  • Kynurenic Acid / metabolism
  • Substrate Specificity
  • Transaminases / metabolism*


  • Keto Acids
  • Transaminases
  • kynurenine-oxoglutarate transaminase
  • Kynurenic Acid
  • Cysteine