Biosynthesis of .BETA.-(isoxazolin-5-on-2-yl) alanine, the precursor of the neurotoxic amino acid .BETA.-N-oxalyl-L-.ALPHA.,.BETA.-diaminopropionic acid.
2-yl)alanine (BIA), a biosynthetic precursor of the neurotoxic amino acid beta-N-oxalyl-L-alpha,beta-diaminopropionic acid (ODAP), was confirmed to be derived from O-acetyl-L-serine (OAS) and isoxazolin-5-one by cysteine synthase in higher plants. Some properties of this enzyme in the biosynthesis of BIA are described.
isoxazolylalanine isomers, beta-(isoxazolin-5-on-2-yl)-L-alanine (BIA, 1) and beta-(isoxazolin-5-on-4-yl)-L- alanine (TAN-950A, 2) were confirmed to be derived from O-acetyl-L-serine (OAS) and isoxazolin-5-one by cysteine synthases (CSases) with a different ratio in different plant parts. Some properties of this enzyme in the biosynthesis of both isomers are described.