GENERATION OF SPECIFIC DEOXYNOJIRIMYCIN-TYPE INHIBITORS OF THE NONLYSOSOMAL GLUCOSYLCERAMIDASE

The existence of a non-lysosomal glucosylceramidase in human cells has been documented (van Weely, S,, Brandsma, M., Strijland, A., Tager, J , M., and Aerts, J. M, F, G. (1993) Biochim, Biophys, Acta 1181, 55-62 ), Hypothetically, the activity of this enzyme, which is localized nea r the cell surface, may influence ceramide-mediated signaling processe s. To obtain insight in the physiological importance of the non-lysoso mal glucosylceramidase, the availability of specific inhibitors would be helpful. Here we report on the generation of hydrophobic deoxynojir imycin (DNM) derivatives that potently inhibit the enzyme. The inhibit ors were designed on the basis of the known features of the non-lysoso mal glucosylceramidase and consist of a DNM moiety, an N-alkyl spacer, and a large hydrophobic group that promotes insertion in membranes, I n particular, N-(5-adamantane-1-yl-methoxy)pentyl)-DNM is a very power ful inhibitor of the non-lysosomal glucosylceramidase at nanomolar con centrations. At such concentrations, the lysosomal glucocerebrosidase and alpha-glucosidase, the glucosylceramide synthase, and the N-linked glycan-trimming alpha-glucosidases of the endoplasmic reticulum are n ot affected.