The Catalytic Machinery of a Key Enzyme in Amino Acid Biosynthesis

Figure 7

Catalytic mechanism of the reversible aspartate β-semialdehyde dehydrogenase-catalyzed conversion of ASA to aspartyl phosphate. (a) Tetrahedral intermediate derived from nucleophilic attack on ASA. (b) Acyl-enzyme intermediate produced by hydride transfer to NADP. (c) Proposed tetrahedral intermediate obtained from phosphate attack on the acyl-enzyme.