The pro sequence of lactase‐phlorizin hydrolase is required for the enzyme to reach the plasma membrane

Abstract
Various cDNAs coding for part or all of human pre‐pro lactase‐phlorizin hydrolase (pre‐proLPH) were transfected into COS cells and the subcellular location of the lactase‐related proteins assessed. Only the complete proLPH reached the plasma membrane. LPH without the pro sequence, and a construct containing the pro sequence and the lactase domain of mature LPH, accumulated intracellularly; the pro sequence with no mature domain was secreted. We conclude that the pro sequence is important for LPH to be transported to the cell surface.