Dipeptidyl peptidase IV (DPPIV) activity in Caiman latirostris and Caiman yacare.

MARIA VIRGINIA PARACHÚ MARCÓ; PABLO ARIEL SIROSKI; MERCHANT, MARK; GISELA LAURA POLETTA; HUGO ORTEGA

Manaos

Congreso; 20th Working Meeting of the Crocodile Specialist Group of the Survival Comission of IUCN; 2010

Crocodile Specialist Group (CSG)

The Dipeptidyl peptidase IV (DPPIV) plays an important role as physiological regulator of a number of peptides that serve as biochemical messengers within the immune system, among others. DPPIV can occur in a soluble form, or as part of the membrane of many cells, and has broad substrate specificity. The presence of DPPIV activity resulted in cleavage of AFC from a dipeptide substrate, producing large increases in fluorescent intensities that were measured spectrofluorimetrically. The DPPIV action was identified and characterized in plasma of wild specimens of C. latirostris and C. yacare at different times, temperatures and concentrations. The enzyme activity was lower in C. yacare than in C. latirostris at all temperatures tested, increasing significantly only in C. yacare at high temperatures, while in C. latirostris showed a strong correlation from the initial temperature. This difference between species could be attributed to its environmental performance. Similarly, plasma exposure of DPPIV in both species showed a time-dependent, although curves seem different between them. These results show that plasma activity of DPPIV was different between two caiman studied, may be as a consequence of differences in susceptibility to infection among them. The values found in this study are higher than those reported for other animals and humans, demonstrating another characteristic of the efficient immune system of crocodilians.