IUBMB Enzyme Nomenclature


Accepted name: uracilylalanine synthase

Reaction: O-acetyl-L-serine + uracil = 3-(uracil-1-yl)-L-alanine + acetate

For diagram of reaction click here.

Glossary: O-acetyl-L-serine = (2S)-3-acetyloxy-2-aminopropanoic acid
3-(uracil-1-yl)-L-alanine = L-willardiine
3-(uracil-3-yl)-L-alanine = L-isowillardiine

Other name(s): O3-acetyl-L-serine acetate-lyase (adding uracil); isowillardiine synthase; willardiine synthase; O3-acetyl-L-serine:uracil 1-(2-amino-2-carboxyethyl)transferase

Systematic name: O-acetyl-L-serine:uracil 1-(2-amino-2-carboxyethyl)transferase

Comments: Both L-willardiine and L-isowillardiine are produced in the reaction. Not identical with EC cysteine synthase.

Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, CAS registry number: 113573-73-2


1. Ahmmad, M.A.S., Maskall, C.S. and Brown, E.G. Partial-purification and properties of willardiine and synthase activity from Pisum sativum. Phytochemistry 23 (1984) 265-270.

2. Ikegami, F., Kaneko, M., Lambein, F., Kuo, Y.-H. and Murakoshi, I. Difference between uracilylalanine synthases and cysteine synthases in Pisum sativum. Phytochemistry 26 (1987) 2699-2704.

3. Murakoshi, I., Ikegami, F., Ookawa, N., Ariki, T., Haginiwa, J., Kuo, Y.-H. and Lambein, F. Biosynthesis of the uracilylalanines willardiine and isowillardiine in higher plants. Phytochemistry 17 (1978) 1571-1576.

[EC created 1990 as EC, transferred 2002 to EC]

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