N-(9Z-octadecenoyl)-sphing-4-enine-1-phosphate(in) <=> N-(9Z-octadecenoyl)-sphing-4-enine-1-phosphate(out)
n-(9z-octadecenoyl)-sphing-4-enine-1-phosphate(in) <=> n-(9z-octadecenoyl)-sphing-4-enine-1-phosphate(out)