PROSITE documentation PDOC00514Aminotransferases class-V pyridoxal-phosphate attachment site
Description
Aminotransferases share certain mechanistic features with other pyridoxal-phosphate dependent enzymes, such as the covalent binding of the pyridoxal-phosphate group to a lysine residue. On the basis of sequence similarity, these various enzymes can be grouped [1,2] into subfamilies. One of these, called class-V, currently consists of the following enzymes:
- Phosphoserine aminotransferase (EC 2.6.1.52), an enzyme which catalyzes the reversible interconversion of phosphoserine and 2-oxoglutarate to 3-phosphonooxypyruvate and glutamate. It is required both in the major phosphorylated pathway of serine biosynthesis and in pyridoxine biosynthesis. The bacterial enzyme (gene serC) is highly similar to a rabbit endometrial progesterone-induced protein (EPIP), which is probably a phosphoserine aminotransferase [3].
- Serine--glyoxylate aminotransferase (EC 2.6.1.45) (SGAT) (gene sgaA) from Methylobacterium extorquens.
- Serine--pyruvate aminotransferase (EC 2.6.1.51). This enzyme also acts as an alanine--glyoxylate aminotransferase (EC 2.6.1.44). In vertebrates, it is located in the peroxisomes and/or mitochondria.
- Isopenicillin N epimerase (gene cefD). This enzyme is involved in the biosynthesis of cephalosporin antibiotics and catalyzes the reversible isomerization of isopenicillin N and penicillin N.
- NifS, a protein of the nitrogen fixation operon of some bacteria and cyanobacteria. The exact function of nifS is not yet known. A highly similar protein has been found in fungi (gene NFS1 or SPL1).
- The small subunit of cyanobacterial soluble hydrogenase (EC 1.12.-.-).
- Hypothetical protein ycbU from Bacillus subtilis.
- Hypothetical protein YFL030w from yeast.
The sequence around the pyridoxal-phosphate attachment site of this class of enzyme is sufficiently conserved to allow the creation of a specific pattern.
Expert(s) to contact by email: Last update:November 1997 / Pattern and text revised.
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References
1 | Authors | Ouzounis C. Sander C. |
Title | Homology of the NifS family of proteins to a new class of pyridoxal phosphate-dependent enzymes. | |
Source | FEBS Lett. 322:159-164(1993). | |
PubMed ID | 8482384 |
2 | Authors | Bairoch A. |
Source | Unpublished observations (1992). |
3 | Authors | van der Zel A. Lam H.-M. Winkler M.E. |
Source | Nucleic Acids Res. 17:8379-8379(1989). |
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