Immunohistochemical localization of dipeptidyl peptidase IV in rat digestive organs.

Subcellular localization of dipeptidyl peptidase IV in rat kideny and small intestine.

“…Our results were in agreement with those of previous studies (2,3,5,7,9,10,16), and confirmed the evidence that DPP IV is a brush border membrane peptidase. Furthermore, using a pre-embedding peroxidase labeled antibody (Fab' fragments) technique, we were able to more precisely determine the subcellular localization of DPP IV in these organs.…”

“…Furthermore, using a pre-embedding peroxidase labeled antibody (Fab' fragments) technique, we were able to more precisely determine the subcellular localization of DPP IV in these organs. Especially in some enterocytes, DPP IV immunoreactivity was found in the cytoplasmic vesicles, lysosomes and the Golgi apparatus, whereas in our previous study we reported no immunoreaction product could be detected in any cytoplasmic organelle (16). This difference in the results might be due to the difference in the penetration of the immunological reagents.…”

“…Using histochemical (3-5, 7, 9, 10) and immunohistochemical techniques (2,7,16), DPP IV has been localized on the brush border of the proximal tubules in the kidney and enterocytes in the small intestine of various animals including human. However, these studies have been restricted largely to the light-microscopic level, and only a limited amount of information on the subcellular localization of this enzyme is available.…”

Cryptdins: antimicrobial defensins of the murine small intestine

“…PC contain an elaborate endoplasmic reticulum, a highly developed Golgi region, and many large (1to 3-,um) apical secretory granules (53) that contain lysozyme (6). They also contain immunoglobulin A (43), phospholipase A2 (49), dipeptidyl peptidase (40), epidermal growth factor (38), and tumor necrosis factor mRNA (23), equipping them to exert wide-ranging effects on the small intestine function. The lysozyme found in mouse PC granules is a distinct isoform (P-lysozyme) whose primary structure differs from that of the less cationic M-lysozyme that is present in macrophages, granulocytes, and many secretions (14,22).…”

Complementary action of dipeptidyl peptidase IV and aminopeptidase M in the digestion of β-casein

“…The combined action of the intestinal brush border aminopeptidases M and A, the cytosolic dipeptidases of enterocytes and the pancreatic carboxypeptidases appear to be entirely sufficient for complete digestion of peptides derived from nutritional proteins (Smith et al 1983;Jungermann & Mohler, 1980) and there seems to be no necessity for an additional peptidase with the unique specificity of dipeptidyl peptidase IV (DP IV). However, this peptidase (which cleaves dipeptides from the N-termini of larger peptides, provided that the penultimate residue is a proline) covers the intestinal microvilli in relatively large amounts (Noren et al 1979;Sahara et al 1983;Danielsen et al 1983). Thefore it is reasonable to assume an involvement of this peptidase in protein digestion, especially of proline-rich proteins.…”