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Kinetic and ultraviolet-visible spectral techniques were utilized to investigate the interaction of Escherichia coli cystathionine beta lyase (CBL) and aminoethoxyvinylglycine (AVG). The results indicated that AVG can act as a slow-binding inhibitor of CBL. X-ray crystallography revealed the spatial structure of the CBLAVG complex as compatible with a ketimine as the reaction product. The structure suggested a binding mode for rhizobitoxine.

The crystal structures of five complexes of Escherichia coli dihydrodipicolinate synthase (DHDPS) with substrates, substrate analogs and inhibitors are shown. These include the complexes of DHDPS with pyruvate, pyruvate and the L-aspartate beta-semialdehyde analog succinate beta-semialdehyde, the inhibitor alpha-ketopimelic acid, dipicolinic acid and the natural feedback inhibitor L-lysine. The kinetics of inhibition were investigated and the binding site of the L-lysine was determined. (4S)-hydroxy-2,3,4,5-tetrahydro-(2S)-dipicolinic acid was identified as the only product of the reaction catalyzed by DHDPS.

Escherichia coli threonine synthase (Ts) catalyzes threonine synthesis from HSerP, deamination and half-transamination reactions, depending on the nature of the substrate. The stabilization of kinetically competent quinonoidal intermediate is an outstanding feature of Ts catalysis.

The isolation annd characterization of a carbamate hydrolase gene from Arthrobacter oxydans P52 were reported. A monomeric phenylcarbamate hydrolase (phenmedipham hydrolase) of about 55-kDa molecular weight was purified to homogeneity. It was found that the gene for phenylcarbamate degradation (pcd) is plasmid encoded. The pcd gene encoding the enzyme was then cloned and sequenced. Sequence comparisons revealed homology of the phenmedipham hydrolase with esterases of eukaryotic origin.