Chitinase in goat serum. Preliminary purification and characterization.

Abstract

1. A glycol‐chitin‐splitting enzyme without lysozyme (muramidase) activity was found in serum from various animals. Goat, cow, hen, sheep and pig possessed high activity. No activity was found in serum from man, monkey, horse, dog, cat, rabbit, guinea‐pig or hamster.2. Glycol chitin has been used as a substrate in purification and characterization. A viscosimetric assay with the use of this substrate was found to be a convenient method.3. By means of ammonium sulphate fractionation of goat serum and subsequent gel chromatography a 100‐fold purification of the enzyme was obtained.4. The purified enzyme has its optimal activity around pH 1.65 with glycol chitin as a substrate and, when incubated at 50 °C for 60 min, the optimal stability is in the pH interval 3.5–6.5. The pI determined by isoelectric focusing is 4.85 and the molecular weight assessed by gel chromatography is around 60000.5. The purified goat serum enzyme degrades colloidal chitin with an optimum at pH 5.5 and is thus defined as a chitinase. Goat anti‐human lysozyme serum does not inhibit the purified chitinase.6. To elucidate the origin of the serum chitinase, the concentration of the enzyme was determined in various organ tissues and body fluids. The highest activity with the exception of serum was found in the wall of the fourth stomach of goat and cow.