What is "anhydrosialidase"

In enzymology, an anhydrosialidase is an enzyme that catalyzes the chemical reaction

Elimination of alpha-sialyl groups in N-acetylneuraminic acid glycosides, releasing 2,7-anhydro-alpha-N-acetylneuraminate

This enzyme belongs to the family of lyases, specifically those carbon-oxygen lyases acting on polysaccharides. The systematic name of this enzyme class is glycoconjugate sialyl-lyase (2,7-cyclizing). Other names in common use include anhydroneuraminidase, sialglycoconjugate N-acylneuraminylhydrolase (2,7-cyclizing), and sialidase L.