Comparative inhibition by substrate analogues 3-methoxy- and 3-hydroxydesaminokynurenine and an improved 3 step purification of recombinant human kynureninase.

Background: Kynureninase is a key enzyme on the kynurenine pathway of tryptophan metabolism. One of the end products of the pathway is the neurotoxin quinolinic acid which appears to be responsible for neuronal cell death in a number of important neurological diseases. This makes kynureninase a possible therapeutic target for diseases such as Huntington's, Alzheimer's and AIDS related dementia, and the development of potent inhibitors an important research aim.

Purification and biochemical characterization of some of the properties of recombinant human kynureninase.

Recombinant human kynureninase (L-kynurenine hydrolase, EC 3.7.1.

2-Amino-4-[3'-hydroxyphenyl]-4-hydroxybutanoic acid; a potent inhibitor of rat and recombinant human kynureninase.

A novel structural analogue of kynurenine, 2-amino-4-[3'-hydroxyphenyl]-4-hydroxybutanoic acid 6, was synthesised as an inhibitor of kynureninase. The compound had a significant inhibitory effect on kynureninase from both rat and human, giving a K(i) of 100 nM. It was thus found that removal of the aryl amino group coupled with a reduction of the carbonyl group at position 7 of the alanine side chain greatly enhanced potency of the inhibitor.