title: Lyase-catalyzed degradation of alginate in the gelled state: effect of gelling ions and lyase specificity.
abstract: Lyase-catalyzed degradation has been proposed as a more cell-friendly alternative to dissolution of alginate gels than using chelating agents. In this study, we investigated the effect of lyase specificity on degradation of alginate gels, including the effect of crosslinking ions with different affinity for the polymer. Degradation kinetics and products were analyzed. In particular, the degradation products were characterized using novel methods for alginate sequence determination by chromatography. Lyase-catalyzed gel disruption worked well for gels crosslinked with calcium, but was less effective when barium was included in the gel formulation. The importance of crosslinking of long G-blocks in maintaining the structural integrity of the gels was identified. The failure to degrade these long G-blocks, either due to protection of the G-blocks by strong ionic crosslinking or due to lack of lyase activity on G-G linkages, resulted in retained resistance to mechanical disruption of the gel.
authors.affiliation: Department of Biotechnology, Norwegian University of Science and Technology (NTNU), Sem Sælands vei 6-8, N-7491 Trondheim, Norway. Electronic address: kjetil.o.formo@ntnu.no.
authors.forename: Kjetil
authors.initials: K
authors.lastname: Formo
authors.affiliation: Department of Biotechnology, Norwegian University of Science and Technology (NTNU), Sem Sælands vei 6-8, N-7491 Trondheim, Norway. Electronic address: olav.a.aarstad@ntnu.no.
authors.forename: Olav Andreas
authors.initials: OA
authors.lastname: Aarstad
authors.affiliation: Department of Biotechnology, Norwegian University of Science and Technology (NTNU), Sem Sælands vei 6-8, N-7491 Trondheim, Norway. Electronic address: gudmund.skjak-brak@ntnu.no.
authors.forename: Gudmund
authors.initials: G
authors.lastname: Skjåk-Bræk
authors.affiliation: Department of Biotechnology, Norwegian University of Science and Technology (NTNU), Sem Sælands vei 6-8, N-7491 Trondheim, Norway; Central Norwegian Regional Health Authority, St. Olav's Hospital, Trondheim University Hospital, Trondheim, Norway. Electronic address: berit.l.strand@ntnu.no.
authors.forename: Berit L
authors.initials: BL
authors.lastname: Strand
mesh_terms: D000464:Alginates / Q000737:chemistry / Q000378:metabolism*; D002384:Catalysis; D005782:Gels / Q000737:chemistry / Q000378:metabolism*; D020723:Glucuronic Acid / Q000737:chemistry / Q000378:metabolism; D006603:Hexuronic Acids / Q000737:chemistry / Q000378:metabolism; D007477:Ions; D011133:Polysaccharide-Lyases / Q000737:chemistry / Q000378:metabolism*
chemical_list: D000464:Alginates; D005782:Gels; D006603:Hexuronic Acids; D007477:Ions; D020723:Glucuronic Acid; D011133:Polysaccharide-Lyases
keywords: Alginate; Alginate gel; G-block; Lyase