Alkaline phosphatase removes 5' phosphate groups from vector so that prevents self-ligation of the vector and facilitates the ligation of other DNA fragments into the vector.
Background
Materials and Reagents
Vector DNA
Restriction enzymes (New England Biolabs)
Alkaline phosphatase: Calf intestinal alkaline phosphatase (CIP) (New England Biolabs, catalog number: M0290 ) or Shrimp Alkaline Phosphatase (SAP) (Promega Corporation, catalog number: M8201 )