Accepted Name |
N-acetyl-demethylphosphinothricin P-methyltransferase
|
Alternative Name(s) |
P-methylase |
Reaction catalysed |
AH2 + N-acetyl-demethyl-L-phosphinothricin + 2 S-adenosyl-L-methionine <=> 5'-deoxyadenosine + A + 2 H(+) + L-methionine + N-acetyl-L-phosphinothricin + S-adenosyl-L-homocysteine |
Comment(s) |
- The enzyme was originally characterized from bacteria that produce
the tripeptides bialaphos and phosalacine, which inhibit plant and
bacterial glutamine synthetases.
- It is a radical S-adenosyl-L-methionine (SAM) enzyme.
- According to the proposed mechanism, the reduced iron-sulfur center
donates an electron to SAM, resulting in homolytic cleavage of the
carbon-sulfur bond to form a 5'-deoxyadenosyl radical that abstracts
the hydrogen atom from the P-H bond of the substrate, forming a
phosphinate-centered radical.
- This radical reacts with methylcob(III)alamin to produce the
methylated product and cob(II)alamin, which is reduced by an unknown
donor to cob(I)alamin.
- A potential route for restoring the latter back to
methylcob(III)alamin is a nucleophilic attack on a second SAM
molecule.
- The enzyme acts in vivo on N-acetyl-demethylphosphinothricin-L-
alanyl-L-alanine or N-acetyl-demethylphosphinothricin-L-alanyl-L-
leucine, the intermediates in the biosynthesis of bialaphos and
phosalacine, respectively.
- This transformation produces the only example of a carbon-phosphorus-
carbon linkage known to occur in nature.
|
Cross-references |
BRENDA | 2.1.1.326 |
EC2PDB | 2.1.1.326 |
ExplorEnz | 2.1.1.326 |
PRIAM enzyme-specific profiles | 2.1.1.326 |
KEGG Ligand Database for Enzyme Nomenclature | 2.1.1.326 |
IUBMB Enzyme Nomenclature | 2.1.1.326 |
IntEnz | 2.1.1.326 |
MEDLINE | Find literature relating to 2.1.1.326 |
MetaCyc | 2.1.1.326 |
Rhea expert-curated reactions | 2.1.1.326 |
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