assay for phosphoinositide-specific phospholipase C and the effect of pyridoxal-5-phosphate on the assay

In platelets, the major stimulatory second messengers are inositol 1, 4, 5 triphosphate [IP3] and 1,2-diacyiglycerol [DAG] produced upon the hydrolysis of phosphoinositides by phosphoinositide-speciftc phospholpase C [P1-PLC]. Pyridoxal-5-phosphate [PLP] is well known as a potent inhibitor of platelet aggregation. The mechanism[s] of its inhibitory action remains to be elucidated. P1-PLC was assayed and the effect of PLP on the assay was examined in an attempt to explain the nature of the inhibitory effect of PLP on platelet function. The assay was satisfactory and was inhibited by PLP with full inhibition at 10mMPLP