ID   2.1.1.326
DE   N-acetyl-demethylphosphinothricin P-methyltransferase.
AN   P-methylase.
CA   AH2 + N-acetyl-demethyl-L-phosphinothricin + 2 S-adenosyl-L-methionine =
CA   5'-deoxyadenosine + A + 2 H(+) + L-methionine + N-acetyl-L-
CA   phosphinothricin + S-adenosyl-L-homocysteine.
CC   -!- The enzyme was originally characterized from bacteria that produce
CC       the tripeptides bialaphos and phosalacine, which inhibit plant and
CC       bacterial glutamine synthetases.
CC   -!- It is a radical S-adenosyl-L-methionine (SAM) enzyme.
CC   -!- According to the proposed mechanism, the reduced iron-sulfur center
CC       donates an electron to SAM, resulting in homolytic cleavage of the
CC       carbon-sulfur bond to form a 5'-deoxyadenosyl radical that abstracts
CC       the hydrogen atom from the P-H bond of the substrate, forming a
CC       phosphinate-centered radical.
CC   -!- This radical reacts with methylcob(III)alamin to produce the
CC       methylated product and cob(II)alamin, which is reduced by an unknown
CC       donor to cob(I)alamin.
CC   -!- A potential route for restoring the latter back to
CC       methylcob(III)alamin is a nucleophilic attack on a second SAM
CC       molecule.
CC   -!- The enzyme acts in vivo on N-acetyl-demethylphosphinothricin-L-
CC       alanyl-L-alanine or N-acetyl-demethylphosphinothricin-L-alanyl-L-
CC       leucine, the intermediates in the biosynthesis of bialaphos and
CC       phosalacine, respectively.
CC   -!- This transformation produces the only example of a carbon-phosphorus-
CC       carbon linkage known to occur in nature.
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