Bovine small intestinal beta-galactosidases.

The s-galactosidase activity of the bovine small intestinal mucosa has been studied over the pH range of 3 to 6.2 using different substrates, and in the presence or absence of the inhibitor p-chloromcrcuri-benzoic acid (pCMB). The results suggest the presence of 3 s-galactosidases: a ‘neutral’ s-goalactosidase (lactase) with optimum pH of 5.4, an ‘acid’ s-galactosidase with optimum pH of 4.6, and a ‘hetero’ s-galactosidase with pH optimum of 5.4.