Sodium periodate oxidized cotton yarn as carrier for immobilization of trypsin

Cotton yarn was first oxidized by sodium periodate to introduce aldehyde groups which were able to react with amino groups of trypsin to form Schiffʹs base, and result in cotton yarn immobilized trypsin. The effect of periodate oxidation on the chemical and physical properties of cotton yarn was evaluated by determining aldehyde group content, fineness and tensile strength of yarn. Measurements of protein load from Bradford assay and catalytic activity in hydrolysis of N-α-benzoyl-dl-arginine p-nitroanilide were made for the immobilized enzyme. The maximum amount of immobilized trypsin was 6.1 mg/g dried cotton yarn. Trypsin immobilized on oxidized cotton yarn retained 90% and 72% of the initial activity at 4 °C and 25 °C, respectively, over 60 days of storage in physiological solution.