Separation and identification of enzymatically prepared dephosphorylated products of myo ‐inositolhexakisphosphate using LC‐MS

LC‐MS technique described here is a new way for the separation and direct determination of UV–Vis insensitive inositol phosphates (InsP 2 ‐InsP 6 ). This circumvents the need of radioisotopic labeling and post‐column derivatization techniques. The method involves separation of various enzymatically dephosphorylated derivatives of InsP 6 on C 18 ‐column using MeOH/H 2 O (30:70 v/v) and their identification using electron spray ionization MS in positive ion mode (+pESI‐MS). The LC‐MS studies revealed that the purified phytase from Aspergillus niger van Teighem hydrolyzes InsP 6 in a sequential manner leading to InsP 2 (InsP 2 ·2Na, t R 4.4–4.54 min, base peak m/z 382.9) as the end product.