Family of unknown function (DUF5675). This presumed domain is found in bacteria, archaea, alveolata and caudoviruses. Proteins in this family are typically between 133 and 179 amino acids in length.

Predicted chitinase [General function prediction only].

Chitinase class I.

Glycoside hydrolase family 19, chitinase domain. Chitinases are enzymes that catalyze the hydrolysis of the beta-1,4-N-acetyl-D-glucosamine linkages in chitin polymers. Glycoside hydrolase family 19 chitinases are found primarily in plants (classes I, III, and IV), but some are found in bacteria. Class I and II chitinases are similar in their catalytic domains. Class I chitinases have an N-terminal cysteine-rich, chitin-binding domain which is separated from the catalytic domain by a proline and glycine-rich hinge region. Class II chitinases lack both the chitin-binding domain and the hinge region. Class IV chitinases are similar to class I chitinases, but they are smaller in size due to certain deletions. Despite lacking any significant sequence homology with lysozymes, structural analysis reveals that family 19 chitinases, together with family 46 chitosanases, are similar to several lysozymes including those from T4-phage and from goose. The structures reveal that the different enzyme groups arose from a common ancestor glycohydrolase antecedent to the prokaryotic/eukaryotic divergence.