Purification and characterization of a novel β-1,3-glucanase from Arca inflata and its immune-enhancing effects

A novel β-1,3-glucanase from Arca inflata was purified using chromatography methods. It was determined as a glycoprotein comprising 23.65% carbohydrate content with O-linked glycan and showed specific activity of 90.01 ± 1.2 U/mg against laminarin. The optimal pH and temperature for the activity of the glucanase were 6.0 and 40 °C, respectively. The affinity parameter of the glucanase using laminarin was determined as K_d = 13.09 μM. The activity of the glucanase was 27 ± 2.6% enhanced by 2-mM Mn²⁺ ions and inhibited by 40-50% using 2-mM Zn²⁺, Cu²⁺, or Ba²⁺ ions. The glucanase showed an endo-type cleavage mode and hydrolyzed laminarin into glucoses, disaccharides, trioligosaccharides, and tetraoligosaccharides. Otherwise, the glucanase exhibited immune-enhancing effects via significantly increasing the phagocytic activity of macrophages and inducing the release of nitric oxide, tumor necrosis factor α, and interleukin-6 in RAW264.7 cells. It might be used as a bifunctional additive for the food industry.