Synthesis and Properties of a Photoactivatable Analogue of Psychosine (β‐Galactosylsphingosine)

Photoaffinity probes: The first synthesis of a photoaffinity probe of psychosine (blue) is reported, where benzophenone (red) is tethered as a crosslinking moiety. This photo-psychosine probe (shown) displayed a similar potency as psychosine in stimulating Ca2+ flux in U937 cells, suggesting that it may be useful for labeling and identifying the still unidentified psychosine receptor(s) by mass spectrometry.