Bilanofos is a natural product formed during
the fermentation of Streptomyces hygroscopicus. It
is readily soluble in water and insoluble in organic
solvents such as acetone, ethanol, benzene, and
hexane (9).
Bilanophos is a GS inhibitor. In
the plant, bilanofos is metabolized to L-glufosinate,
which inhibits the enzyme GS. Ammonium ions
rapidly accumulate in the plant, and photosynthesis
is inhibited, leading to rapid death of the plant. It is
inactivated in soil.
Bialaphos[peptide derivative of PPT (PPT linked to
two L-alanine moieties)] was originally isolated from cultures
of Streptomyces viridochromogenes (87) and Streptomyces
hygroscopicus (88). L-PPT is the natural isomer,
and it was the first natural amino acid found to contain a
phosphinic group. PPT strongly inhibited glutamine synthetase
activity in E. coli (87), and Hoechst Ag patented
it as a herbicide after its phytotoxicity was discovered
(89). Bialaphos was patented as a herbicide (90) and
is marketed in Japan (91). Glufosinate (ammonium salt of
PPT) is the synthesized commercial product. Bialaphos is
hydrolyzed by plant and soil microbial peptidases to yield
the active herbicide (PPT) (92–94). PPT is also rapidly
degraded, with half-life of 4 to 7 days in soils (95). In a
test of 300 bacterial isolates from soil, all strains degraded
L-PPT to the 2-oxo analog of PPT via transamination (96).
ChEBI: A tripeptide comprising one L-phosphinothricyl and two L-alanyl units joined in sequence.
The compound was launched as a nonselective contact herbicide in 1984.
When 14C-bialaphos [L-2-amino-4-
[(hydroxy)(methyl)phosphinoyl]butyryl-L-alanyl-L-
alanine] is administered in an aqueous solution to
mice, the metabolite of bialaphos which is identified as
2-amino-4-[(hydroxy)(methyl)phosphinoyl]butyric acid
is excreted in the feces and urine.
The major metabolite following
oral administration in the mouse was 2-amino-4-
(hydroxy)(methyl)phosphinyl)butyric acid, which was
eliminated in feces.
