IUBMB Enzyme Nomenclature


Accepted name: L-glutamate-5-semialdehyde N-acetyltransferase

Reaction: acetyl-CoA + L-glutamate-5-semialdehyde = CoA + N-acetyl-L-glutamate 5-semialdehyde

Other name(s): MPR1 (gene name); MPR2 (gene name)

Systematic name: acetyl-CoA:L-glutamate-5-semialdehyde N-acetyltransferase

Comments: The enzyme, characterized from the yeast Saccharomyces cerevisiae Σ1278b, N-acetylates L-glutamate-5-semialdehyde, an L-proline biosynthesis/utilization intermediate, into N-acetyl-L-glutamate 5-semialdehyde, an intermediate of L-arginine biosynthesis, under oxidative stress conditions. Its activity results in conversion of L-proline to L-arginine, and reduction in the concentration of L-glutamate 5-semialdehyde and its equilibrium partner, (S)-1-pyrroline-5-carboxylate, which has been linked to production of reactive oxygen species stress. The enzyme also acts on (S)-1-acetylazetidine-2-carboxylate, a toxic L-proline analog produced by some plants, resulting in its detoxification and conferring resistance on the yeast.

Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, PDB, CAS registry number:


1. Shichiri, M., Hoshikawa, C., Nakamori, S. and Takagi, H. A novel acetyltransferase found in Saccharomyces cerevisiae Σ1278b that detoxifies a proline analogue, azetidine-2-carboxylic acid. J. Biol. Chem. 276 (2001) 41998-42002. [PMID: 11555637]

2. Nomura, M. and Takagi, H. Role of the yeast acetyltransferase Mpr1 in oxidative stress: regulation of oxygen reactive species caused by a toxic proline catabolism intermediate. Proc. Natl Acad. Sci. USA 101 (2004) 12616-12621. [PMID: 15308773]

3. Nishimura, A., Kotani, T., Sasano, Y. and Takagi, H. An antioxidative mechanism mediated by the yeast N-acetyltransferase Mpr1: oxidative stress-induced arginine synthesis and its physiological role. FEMS Yeast Res. 10 (2010) 687-698. [PMID: 20550582]

4. Nishimura, A., Nasuno, R. and Takagi, H. The proline metabolism intermediate Δ1-pyrroline-5-carboxylate directly inhibits the mitochondrial respiration in budding yeast. FEBS Lett. 586 (2012) 2411-2416. [PMID: 22698729]

5. Nasuno, R., Hirano, Y., Itoh, T., Hakoshima, T., Hibi, T. and Takagi, H. Structural and functional analysis of the yeast N-acetyltransferase Mpr1 involved in oxidative stress tolerance via proline metabolism. Proc. Natl Acad. Sci. USA 110 (2013) 11821-11826. [PMID: 23818613]

[EC created 2018]

Return to EC 2.3.1 home page
Return to EC 2.3 home page
Return to EC 2 home page
Return to Enzymes home page
Return to IUBMB Biochemical Nomenclature home page