Select the correct combination of an enzyme, its substrate and the optimal pH for its action.

Pepsin digests proteins into proteoses and peptones. HCl provides the acidic pH (pH 1.8) optimal for pepsin. Maltose is digested by maltase (not amylase). Trypsin digests proteins (not starch). Enzymes of pancreatic juice  (e.g., nuclease) and intestinal juice are effective in alkaline medium (not acidic medium).