Characterization of Chitotriosidase Enzyme Activity in the Serum of the American Alligator (Alligator mississippiensis)

摘要

Chitotriosidase (ChT) is an endoglucosaminidase enzyme that cleaves chi-tinous substrates and has been strongly associated with innate immune activ-ity and the ability to identify non-selftissues. This enzyme activity was de-tected and characterized the serum from the American alligator (Alligator mississippiensis) using a fluorometric probe. Alligator serum exhibited vo-lume-dependent activity, with activity (2.1 ± 0.3 μmol/min) observed at dilu-tions as low as a 1:150, and maximum activity (5.2 ± 0.6 μmol/min) measured at a dilution of 1:30. Alligator serum ChT showed linear activity for approx-imately 20 min, at which time activity decreased exponentially, presumably due to the depletion of substrate. In addition, the ChT activity in alligator se-rum was temperature-dependent with low activity at 5℃, a sharp increase from 10℃ - 30℃, and maximal activity from 30℃ - 40℃. The activity was inhibited in the presence of water-soluble chitin, but not mannan, indicating the specificity of the enzyme. The presence of ChT in alligator serum is likely to be partially responsible for the potent innate immune system of these cro-codylians, and particularly antifungal activities.