Distribution and properties of neutral ceramidase activity in rat intestinal tract

Digestive Diseases and Sciences
P LundgrenR D Duan

Abstract

Ceramide plays an important role in regulating cell proliferation and apoptosis. Recent studies indicate that generation of ceramide in the intestine from sphingomyelin hydrolysis may be implicated in colon cancer development. The enzymes that catalyze the further hydrolysis of ceramide in the intestine have, however, not been well investigated. Our data reveal the existence of a ceramidase (EC 3.5.1.23) in rat intestinal mucosa with an optimal pH of 7.0. One milligram of mucosal protein is able to hydrolyze 44.0+/-9.6 nmol of ceramide in 1 hr. The activity is low in the proximal duodenum and increases to a plateau in the proximal jejunum. The activity is then similar throughout the small intestine, until it declines in the distal part of ileum. Some activity is also detectable in the colon. The activity increases slightly in the presence of monomeric bile salt concentrations and sharply at the critical micellar concentration. Similar patterns were observed for both primary (taurocholate) and secondary (taurodeoxycholate) bile salts. The addition of Triton X-100 enhances the ceramidase activity at optimal bile salt concentration. The reaction is linear with time for the first 20 min and the hydrolytic rate declines slowly there...Continue Reading

Citations

Jun 26, 2004·American Journal of Physiology. Gastrointestinal and Liver Physiology·Maria OlssonAke Nilsson
Jun 19, 2004·American Journal of Physiology. Gastrointestinal and Liver Physiology·Jun WuRui-Dong Duan
Dec 29, 2005·The Journal of Biological Chemistry·Mari KonoRichard L Proia
Mar 16, 2011·Journal of Digestive Diseases·Rui-Dong Duan
Oct 15, 2003·Gene·Moonsuk S ChoiAnil B Mukherjee
Jan 6, 2007·Biochimica Et Biophysica Acta·R D DuanA Nilsson

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