Fig. 2.

Mouse SMSr catalyzes CPE production. A: TLC separation of reaction products obtained when NBD-Cer was incubated with lysates of yeast strains expressing hSMSr or mSMSr. Part of the TLC (control and hSMSr) was already published (24), but is illustrated here for immediate comparison. B: Different molecular species of CPE detected by LC-MS/MS analysis (neutral loss of 141) after alkaline hydrolysis of glycerolipids in SMSr-expressing Conzelmann yeast strain in which endogenous ceramide synthases were substituted for mouse ceramide synthase 5; see (24) for further details. C: TLC separation of reaction products obtained when NBD-Cer was incubated with lysates of yeast strains expressing hSMSr or hSMSrD348E proving missing catalytic activity of the point mutated protein. Immunoblot analysis (below TLC) confirms that equal amounts of protein were used. hSMSr, human SMSr; mSMSr, mouse SMSr.