Characterization of a GH50 β-Agarase: A Biotechnological Tool for Preparing Oligosaccharides from Agarose and Porphyran

Agarase is of vital significance for functional agaro-oligosaccharides production from algal dived agarose. Especially, the exolytic agarases have the advantage of obtaining agaro-oligosaccharides with a specific degree of polymerization. Herein, we cloned and expressed a novel glycoside hydrolase (GH) 50 family β-agarase OUC-PgJC50 from Photobacterium gaetbulicola. The degradation pattern analysis indicated that OUC-PgJC50 not only showed an exolytic activity with main products of neoagarotetraose from hydrolyzing agarose but also show a hydrolytic activity to transform neoagarotetraose into neoagarobiose. This is the first time that the discovery of a neoagarotetraose-producing exolytic GH50 β-agarase possesses the activity to transform neoagarotetraose into neoagarobiose, which provided new insight into the recognition of the degradation mode of agarases. Molecular docking and sequence alignment analysis further revealed the His₆₅₄ residue in OUC-PgJC50 may play a vital role in forming a strong force with l-AHG residue at -4 subsite that helps to produce neoagarotetraose from catalyzing agarose. Moreover, the catalytic ability of OUC-PgJC50 toward another agar polysaccharide porphyran was also described that could hydrolyze porphyran into sulfated oligosaccharides, in which the LA6S-d-Gal was the main products. This study is of vital significance for developing the application range of GH50 β-agarases.

Stability assessment of FDA-approved ramucirumab monoclonal antibody; validated SE-HPLC method for degradation pattern evaluation

Ramucirumab (RAMU) is a recently US Food and Drug Administration-approved monoclonal antibody that is included in various anticancer protocols. It has a structural complexity and high degradation risk that have a significant effect on its safety and effectiveness. The major aim of this work was to assess the degradation pattern of RAMU based on physicochemical characterization. Mechanical agitation, repeated freeze-thaw cycles, pH and temperature were the selected stress conditions to which RAMU samples were subjected. The SE-HPLC method was applied and validated to monitor the RAMU monomer along with its aggregates and/or fragments. The purity of the separated peaks together with system suitability parameters were determined through the calculation of percentage purity and percentage drop in RAMU concentration. The results were interpreted by correlating them with those of dynamic light scattering and reducing and non-reducing sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Samples incubated at pH 2.0-10.0 and 37°C for up to 4 weeks were analysed, recording detection of reversed phase (RP) aggregates and low molecular weight peptide fragments. Similarly, samples under short-term storage conditions of 4 weeks at different temperatures (-20, 2-8, 25, 37 and 50°C) showed low molecular weight peptide fragments but to a lesser extent. These results highlight the alarming effect on RAMU multidose vial efficacy and safety.

Biochemical Characterization and Elucidation of Action Pattern of a Novel Polysaccharide Lyase 6 Family Alginate Lyase from Marine Bacterium Flammeovirga sp. NJ-04

Alginate lyases have been widely used to prepare alginate oligosaccharides in food, agricultural, and medical industries. Therefore, discovering and characterizing novel alginate lyases with excellent properties has drawn increasing attention. Herein, a novel alginate lyase FsAlyPL6 of Polysaccharide Lyase (PL) 6 family is identified and biochemically characterized from Flammeovirga sp. NJ-04. It shows highest activity at 45 °C and could retain 50% of activity after being incubated at 45 °C for 1 h. The Thin-Layer Chromatography (TLC) and Electrospray Ionization Mass Spectrometry (ESI-MS) analysis indicates that FsAlyPL6 endolytically degrades alginate polysaccharide into oligosaccharides ranging from monosaccharides to pentasaccharides. In addition, the action pattern of the enzyme is also elucidated and the result suggests that FsAlyPL6 could recognize tetrasaccharide as the minimal substrate and cleave the glycosidic bonds between the subsites of −1 and +3. The research provides extended insights into the substrate recognition and degradation pattern of PL6 alginate lyases, which may further expand the application of alginate lyases.