**9.3 Inhibition of DAPDC**

Diaminopimelic acid analogues (Fig. 23) have been synthesised to study the inhibition of DAPDC from *B. sphaericus* (Kelland et al., 1986). Mixtures of isomers of Nhydroxydiaminopimelate and N-aminodiaminopimelate are potent competitive inhibitors of DAPDC, with *K*i values of 0.91 mM and 0.1 mM, respectively. Lanthionine sulfoxides (Fig. 23) are good competitive inhibitors, providing about 50% inhibition at 1 mM. Weaker competitive inhibitors include the *meso* and *LL*-isomers of lanthionine sulfone and lanthionine, whereas the *DD*-isomers (Fig. 23) were less effective.

Fig. 23. Inhibitors of DAPDC.
