Worm Breeder's Gazette 4(1): 29

These abstracts should not be cited in bibliographies. Material contained herein should be treated as personal communication and should be cited as such only with the consent of the author.

Purification of Kynureninase from the Nematode C. elegans

S. Siddiqui, P. Babu

The flu-2 X mutants are characterized by a dull greenish-yellow 
autofluorescence of the gut cells and have only 5-6% of the wild type 
kynureninase activity (Babu, P., 1974, Mol.  Gen.  Genet.  135, 39-44).
We have partially purified kynureninase from wild type animals about 
60 fold over the crude extract by ammonium sulphate precipitation, 
chromatography on Sephadex G-150, DEAE cellulose, and affinity 
chromatography on L-kynurenine bound to Sepharose.  The molecular 
weight of the partially purified enzyme as estimated on the basis of 
its elution profile from the Sephadex G-150 column is about 56,000.  
The enzyme requires pyridoxal-5'-phosphate as coenzyme and the pH 
optimum is at pH 8.0 in phosphate or Tris-HCl buffer.
One of the alleles of the flu-2 gene flu-2(t201) has about 15% wild 
type enzyme activity.  Thermal stability tests were carried out on the 
partially purified enzymes from wild type and the (t201) mutant.  The 
two enzymes have different heat stabilities at 60 C.  The t 1/2 for 
the wild type enzyme is 3.5 minutes and for the T201 enzyme is 2.5 
minutes.  This suggests that the two enzymes could be structurally 
different.  Experiments in Gottingen are in progress using some of the 
X-chromosome duplications, isolated by Bob Herman, which include the 
flu-2 region.  We want to look whether there is a gene dosage effect, 
which would indicate that flu-2 may be the structural gene for the 
enzyme kynureninase (EC.