EC |
2.1.3.9 |
Accepted name: |
N-acetylornithine carbamoyltransferase |
Reaction: |
carbamoyl phosphate + N2-acetyl-L-ornithine = phosphate + N-acetyl-L-citrulline |
Glossary: |
N-acetyl-L-citrulline = N5-acetylcarbamoyl-L-ornithine |
Other name(s): |
acetylornithine transcarbamylase; N-acetylornithine transcarbamylase; AOTC; carbamoyl-phosphate:2-N-acetyl-L-ornithine carbamoyltransferase; AOTCase |
Systematic name: |
carbamoyl-phosphate:N2-acetyl-L-ornithine carbamoyltransferase |
Comments: |
Differs from EC 2.1.3.3, ornithine carbamoyltransferase. This enzyme replaces EC 2.1.3.3 in the canonic arginine biosynthetic pathway of several Eubacteria and has no catalytic activity with L-ornithine as substrate. |
Links to other databases: |
BRENDA, EXPASY, KEGG, MetaCyc, PDB, CAS registry number: 890853-54-0 |
References: |
1. |
Shi, D., Morizono, H., Yu, X., Roth, L., Caldovic, L., Allewell, N.M., Malamy, M.H. and Tuchman, M. Crystal structure of N-acetylornithine transcarbamylase from Xanthomonas campestris: a novel enzyme in a new arginine biosynthetic pathway found in several Eubacteria. J. Biol. Chem. 280 (2005) 14366–14369. [DOI] [PMID: 15731101] |
2. |
Morizono, H., Cabrera-Luque, J., Shi, D., Gallegos, R., Yamaguchi, S., Yu, X., Allewell, N.M., Malamy, M.H. and Tuchman, M. Acetylornithine transcarbamylase: a novel enzyme in arginine biosynthesis. J. Bacteriol. 188 (2006) 2974–2982. [DOI] [PMID: 16585758] |
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[EC 2.1.3.9 created 2005] |
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EC |
2.1.3.11 |
Accepted name: |
N-succinylornithine carbamoyltransferase |
Reaction: |
carbamoyl phosphate + N2-succinyl-L-ornithine = phosphate + N-succinyl-L-citrulline |
Glossary: |
N-acetyl-L-citrulline = N5-acetylcarbamoyl-L-ornithine |
Other name(s): |
succinylornithine transcarbamylase; N-succinyl-L-ornithine transcarbamylase; SOTCase |
Systematic name: |
carbamoyl phosphate:N2-succinyl-L-ornithine carbamoyltransferase |
Comments: |
This enzyme is specific for N-succinyl-L-ornithine and cannot use either L-ornithine (see EC 2.1.3.3, ornithine carbamoyltransferase) or N-acetyl-L-ornithine (see EC 2.1.3.9, N-acetylornithine carbamoyltransferase) as substrate. However, a single amino-acid substitution (Pro90 → Glu90) is sufficient to switch the enzyme to one that uses N-acetyl-L-ornithine as substrate. It is essential for de novo arginine biosynthesis in the obligate anaerobe Bacteroides fragilis, suggesting that this organism uses an alternative pathway for synthesizing arginine. |
Links to other databases: |
BRENDA, EXPASY, KEGG, MetaCyc, PDB |
References: |
1. |
Shi, D., Morizono, H., Cabrera-Luque, J., Yu, X., Roth, L., Malamy, M.H., Allewell, N.M. and Tuchman, M. Structure and catalytic mechanism of a novel N-succinyl-L-ornithine transcarbamylase in arginine biosynthesis of Bacteroides fragilis. J. Biol. Chem. 281 (2006) 20623–20631. [DOI] [PMID: 16704984] |
2. |
Shi, D., Yu, X., Cabrera-Luque, J., Chen, T.Y., Roth, L., Morizono, H., Allewell, N.M. and Tuchman, M. A single mutation in the active site swaps the substrate specificity of N-acetyl-L-ornithine transcarbamylase and N-succinyl-L-ornithine transcarbamylase. Protein Sci. 16 (2007) 1689–1699. [DOI] [PMID: 17600144] |
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[EC 2.1.3.11 created 2008] |
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