Caractères et évolution des enzymes chitinolytiques chez les vertébrés infèrieurs |
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Authors: | Ch Jeuniaux G Dandrifosse JC Micha |
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Institution: | Université de Liège, Institut de Zoologie, Laboratoires de Morphologie, Systématique et Ecologie animales et Institut L. Fredericq, Laboratoire de Biochimie Générate et Comparée, 17 Place Delcour, B 4020, Liège, Belgium |
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Abstract: | The activity of chitinases extracted from various organs of different fish, amphibians and reptiles was estimated as a function of pH by using “native” chitin as substrate. Three types of chitinase activity were recorded, suggesting the existence of three different chitinase types: Type 1: (optimum pH; 4.5, no activity at pH 1.0) was found in various organs, such as intestine, pyloric caeca, pancreas, liver, spleen, etc.); Type IIa: (optimum pH; 3.0, weak activity at pH 1.0) was obtained from the gastric mucosa of fish and one species of urodele; Type IIb: (optimum pH; 3.0, strong activity at pH 1.0) was found in the gastric mucosa of reptiles and batrachian anura. Chitinase activity appears to be adapted to the pH of the digestive fluids. A tentative scheme is presented of chitinase evolution among lower vertebrates. |
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Keywords: | Fish Amphibia Reptilia chitinases digestive sysetms evolution |
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