This family contains several bacterial alginate lyase proteins. Alginate is a family of 1-4-linked copolymers of beta -D-mannuronic acid (M) and alpha -L-guluronic acid (G). It is produced by brown algae and by some bacteria belonging to the genera Azotobacter and Pseudomonas. Alginate lyases catalyze the depolymerization of alginates by beta -elimination, generating a molecule containing 4-deoxy-L-erythro-hex-4-enepyranosyluronate at the nonreducing end. This family adopts an all alpha fold.