Lipase-Catalyzed Enantiomeric Resolution of Ceramides

Lipase-catalyzed enantiomeric kinetic resolution of ceramides related to C(16)-sphinganine and C(18)-sphingenine is described. Two hydroxy groups in readily available racemic N-stearoyl-erythro-C(16)-sphinganine were acetylated, and several kinds of lipases were screened for the hydrolysis of this substrate. Among them, a Burkholderia cepacia lipase (SC lipase A, Sumitomo Chemical Co., Ltd.) showed the highest reactivity and enantioselectivity. The rate of hydrolysis and selectivity were greatly affected by some additives. Especially, the combined use of a detergent, Triton X-100, and the solid support, Florisil, for immobilization showed the highest enantioselectivity (E = ca. 170), although the reaction rate turned low. Introduction of a double bond into the substrate (N-stearoyl-erythro-C(18)-sphingenine) also retarded the hydrolysis. By utilizing the preferential hydrolysis of the acetate on the primary hydroxy group, another advantageous feature of this enzyme-catalyzed reaction, the resulting product could directly be used as the glycosyl acceptor for cerebroside synthesis.