YJL060W

(BNA3)

4.12.08



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SGD

Arylformamidase, involved in biosynthesis of nicotinic acid from tryptophan via kynurenine pathway; potential Cdc28p substrate





go molecular function : arylformamidase activity (TAS)

go biological process : NAD biosynthetic process (IMP)

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MIPS

similarity to kynurenine aminotransferase and glutamine- phenylpyruvate transaminase, and other transaminases



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KEGG

BNA3; Arylformamidase, involved in biosynthesis of nicotinic acid from tryptophan via kynurenine pathway; potential Cdc28p substrate [EC:2.6.1.-]; K00841 aminotransferase



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Literature examined:

  1. Panozzo C, et al. (2002) Aerobic and anaerobic NAD+ metabolism in Saccharomyces cerevisiae. FEBS Lett 517, 97-102



YJL060W (BNA3) is currently annotated by SGD/GO as “Arylformamidase, involved in biosynthesis of nicotinic acid from tryptophan via kynurenine pathway”. (E.C. 3.5.1.9 - N-formyl-L-kynurenine + H2O = formate + L-kynurenine). This is based on a “TAS : However, on inspection of the source of the TAS, Panozzoa et al. [8], we read: “Two hypotheses can be advanced to account for the lack of phenotype associated with the bna3 mutation: either bna3 does not encode the arylformamidase or another enzyme can perform the same reaction. … Therefore further experiments will be necessary to resolve this question and to determine if a combination of mutations in these different formyltransferases can lead to a nicotinic acid auxotroph phenotype”. Therefore, this TAS is questionable.



  1. Zabriski, T.M, Jackson, M.D. (2000) Lysine biosynthesis and metabolism in fungi. Nat. Prod. Rep. 17, 85-97.



The closest homologs to YJL060W are annotated as kynurenine-oxoglutarate transaminases. A kyneurenine aminotransferase has been described in the yeast Hansenula schneggii that can utilise α-aminoadipate as an alternative substrate



  1. Masuda, M. and Ogur, M. (1969) Enzymatic and physiological properties of the yeast glutamate-alpha-ketoadipate transaminase. J. Biol. Chem. 244, 5153-8



The molecular mass of YJL060W is 50kDa, while the missing 2A2OA I has a mass of 100kDa – suggesting a dimer.



2A2OA I is known to occur in the mitochondrium [Masuda & Ogur, 1969]. SGD labels YJL060W as occurring in both the mitochondrium and the cytoplasm; but its sequence signals strongly suggests location in the mitochondrium [Panozzo C, et al. (2002)]





Note added 7.4.08



New paper on gene:

Wogulis, M., Chew, E.R., Donohoue, P.D., Wilson, D.K. (2008) Identification of formly kynurenine formamidase and kynurenine aminotransferase from Saccharomyces cerevisiae using crystallographic, bioinformatic and biochemical evidence. Biochemistry 47, 1608-1621.

Present strong evidence that BNA3 is a kynurenine aminotransferase.