Alginate lyase: Review of major sources and enzyme characteristics, structure-function analysis, biological roles, and applications

Alginate lyases, characterized as either mannuronate (EC 4.2.2.3) or guluro nate lyases (EC 4.2.2.11), catalyze the degradation of alginate, a complex copolymer of alpha -L-guluronate and its C5 epimer beta -D-mannuronate. Lya ses have been isolated from a wide range of organisms, including algae, mar ine invertebrates, and marine and terrestrial microorganisms. This review c atalogs the major characteristics of these lyases, the methods fur analyzin g these enzymes, as well as their biological roles. Analysis of primary seq uence data identifies some markedly conserved motifs that should help eluci date functional domains. Information about the three-dimensional structure of a mannuronate lyase from Sphingomonas sp., combined with various mutagen esis studies, has identified residues that are important for catalytic acti vity in several lyases. Characterization of alginate lyases will enhance an d expand the use of these enzymes to engineer novel alginate polymers for a pplications in various industrial, agricultural, and medical fields. In thi s review, we explore both past and present applications of this important e nzyme and discuss its future prospects.