Preparation of phosphopeptide derived fromα_s-casein andβ-casein using immobilized glutamic acid-specific endopeptidase and characterization of their calcium binding

摘要

Phospopeptides that were derived fromα_-CN or β-CN were prepared with immobilized glutamic acid- specific endopeptidase, and their Ca~2+ binding was characterized. α_s-Casein orβ-CN was hyprolyzed in a fluidized bed bioreactor containing 2 ml of immobi- lized glutamic acid-specific endopeptidase by recir- culating 20 ml ofα_s-CN orβ-CN solution(10)mg/ml in 50 m/M Tris.HVl and 0.02/100 NaN_3, pH 8.0)for 3h at 20 deg. C. The molecular masses of casein peptides were monitored by SDS-PAGE. Each hydrolysate was applied to an anion-exchange column using stepwise elution with various concentrations of KCl to separate peptides.