Longitudinal distribution of mucosal enzymes in the human large bowel

The distribution of a series of mucosal enzymes along the large bowel was studied by analysis of homogenized biopsy specimens from five different segments, obtained from 20 control patients. The activities varied significantly between the segments for the membrane enzymes lactase (p less than 0.005), alkaline phosphatase (p less than 0.0005), leucyl-beta-naphthylamidase (p less than 0.0001), and 5'-nucleotidase (p less than 0.001) and the mitochondrial enzyme monoamine oxidase (p less than 0.0005) when tested by analysis of variance modified for repeated measurements. When paired comparisons between segments were evaluated, the enzyme activities of the proximal large bowel were significantly higher than those of distal segments. The levels of sucrase, neutral-alpha-glucosidase, gamma-glutamyltransferase, and lysosomal enzymes remained unchanged throughout the large intestine, as did the protein to DNA ratio. The results are compatible with the theory that different segments of the large bowel have different functions.