Phospholipase C (PLC)

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Phospholipase C (PLC) [EC] hydrolyzes phosphatidylinositol 4,5-bisphosphate to inositol 1,4,5-trisphosphate and diacylglycerol. It has an absolute requirement for calcium and is activated by guanine nucleotide binding proteins (PLC-_), or by receptor tyrosine kinases (PLC-_), or by transglutaminase II (PLC-_). All three vertebrate isoforms of PLC have a plekstrin homolog domain, followed by four EF-hands, a triosephosphate isomerase-like _- barrel catalytic domain, and a C2 domain [56]. Although calcium is absolutely required for activity, it is bound to the catalytic domain. None of the four EF-hands have canonical calcium binding loops nor is Ca2+ bound in the crystal structure [57].