Fig. 4

Degradation patterns of alginate polysaccharide by AlyPB1 and AlyPB2. a Time-course treatment of sodium alginate (1.0 mg/ml) using AlyPB1 at 30 °C. b Time-course treatment of sodium alginate (1.0 mg/ml) using AlyPB2 at 20 °C. The unsaturated oligosaccharide products were analysed through a pre-equilibrated Superdex peptide 10/300 GL column monitored using a UV detector at 235 nm. Degrees of polymerization of oligosaccharides are indicated on the peaks: UDP1, UDP2, UDP3, UDP4, UDP5 and UDP6 represent unsaturated monosaccharide, disaccharide, trisaccharide, tetrasaccharide, pentasaccharide and hexasaccharide; DEH and TPC are both converted products of unsaturated monosaccharide. c Analysis for the degradation orientation of exo-lyase AlyPB2. Time-course treatment of 2-AB-labeled saturated alginate pentasaccharide (2-AB-DP5) (10 pmol) with AlyPB2 at 20 °C. The resulting products were analysed by gel filtration as described above but using a fluorescent detector with an excitation wavelength of 330 nm and an emission wavelength of 420 nm. 2-AB-UDP2, 2-AB-UDP3 and 2-AB-UDP4 represent 2-AB-labeled unsaturated alginate disaccharide, trisaccharide and tetrasaccharide. E (−), control treated with inactivated enzyme