Figure 7 - full size

 

Figure 7.
FIG. 7. The proposed mechanism for the catalytic hydrolysis of the sphingomyelin substrate by SMase I, His12, and His47 participate in the reaction as the acid and base. R and R' represent ceramide 1-phosphate and choline, respectively. The figure was generated using ChemSketch (www.acdlabs.com).

The above figure is reprinted by permission from the ASBMB: J Biol Chem (2005, 280, 13658-13664) copyright 2005.