The present disclosure is generally directed to methods of treating a disease or disorder associated with dysfunctional phosphatidylinositol-specific phospholipase C2 (PLC2), such as cancers and immune system disorders, using Bruton's tyrosine kinase (BTK) reducing molecules, such as BTK degrader molecules.

The present disclosure relates to a synthesis method of -nicotinamide mononucleotide (-NMN) and an intermediate thereof. In the present disclosure, phospholipid metabolism enzymes phospholipase D (PLD) and phospholipase C (PLC) widely present in the biosphere are used as catalysts to prepare -NMN through two-step enzymolysis or one-pot synthesis; and an intermediate, namely phosphatidyl nicotinamide riboside (PNR), is obtained during the two-step enzymolysis. The present disclosure has simple reaction steps, low production cost, and environmental friendliness, and is suitable for large-scale industrial production.