Complex sentence: It catalyses the removal of phosphate groups from the 5' ends of DNA and is frequently used in DNA subcloning as it prevents re-circularisation of vectors and therefore reduces the yield of properly-ligated product.
Split into simpler sentences: It catalyses the removal of phosphate groups from the 5' ends of DNA. It is frequently used in DNA sub-cloning as it prevents re-circularisation of vectors and therefore reduces the yield of properly-ligated product.