Inhibition of acetylpolyamine and spermine oxidases by the polyamine analogue chlorhexidine

Figures & data

Figure 1.  Chemical structures of chlorhexidine and MDL 72527.

Figure 2.  Schematic representation of the APAO and SMO best docking complexes with CHX (top panels) and MDL 72527 (bottom panels) showing proteins residues interacting with the inhibitors. The FAD cofactor (colored in magenta) and the active site His residue (His64 and His82 in APAO and SMO, respectively) are shown for reference.

Figure 3.  Lineweaver–Burk plots reporting reciprocal rate oxidation of N¹-acetyl-Spm by APAO (A) and Spm by SMO (D) versus reciprocal substrate concentrations, in the presence and absence of CHX. To calculate Ki for the inhibition by CHX, the data are also reported by second plot of slopes from Lineweaver–Burk plot versus CHX concentrations (B, APAO; E, SMO), and by Dixon plots reporting reciprocal rate substrate oxidation as a function of CHX concentrations (C, APAO; F, SMO)

Table 1.  Values of K_i for CHX and MDL 72527 binding to APAO and SMO.

Inhibitor	Ki (μM)^a
	APAO	SMO
Chlorhexidine	0.10	0.55
MDL72527b	21.0b	63.0b

^aThe standard deviation is ± 5%.

^bBianchi et al²⁰.