Intestinal lactase-phlorizin hydrolase (LPH): the two catalytic sites; the role of the pancreas in pro-LPH maturation.

Brush border lactase-phlorizin hydrolase carries two catalytic sites. In the human enzyme lactase comprises Glu-1749, phlorizin hydrolase Glu-1273. The proteolytic processing of pro-lactase-phlorizin hydrolase by (rat) enterocytes stops two amino acid residues short of the N-terminus of 'mature' final, brush border lactase-phlorizin hydrolase. Only these two amino acid residues are removed by luminal pancreatic protease(s), probably trypsin.