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Protein Separation Coacervation with Carboxymethyl Cellulose of Different Substitution Degree: Noninteracting Behavior of Bowman-Birk Chymotrypsin Inhibitor

Protein Separation Coacervation with Carboxymethyl Cellulose of Different Substitution Degree: Noninteracting Behavior of Bowman-Birk Chymotrypsin Inhibitor

Authors :
Xiangzhen Kong
Caimeng Zhang
Yufei Hua
Xingfei Li
Yeming Chen
Jie Long
Source :
Journal of agricultural and food chemistry. 66(17)
Publication Year :
2018

Abstract

We first observed that protein/polysaccharide interaction exhibited noninteracting behavior which makes Bowman–Birk chymotrypsin inhibitor (BBI) always free of complexation, being separated from another protein with similar isoelectric points, Kunitz trypsin inhibitor (KTI). Turbidity titrations showed that the electrostatic attractions were much stronger between KTI/BBI (KBi) and carboxymethyl cellulose of higher substitution degree. Unchanged chymotrypsin inhibitory activity (CIA) indicated that BBI had negligible contribution to protein recovery and trypsin inhibitory activity (TIA). Tricine–SDS–PAGE revealed that, at r = 20:1–2:1, unbound BBI was left in the supernatant when bound KTI transferred into precipitates, even if there was excess negative charge. Thus, purified KTI or BBI was achieved easily at the given conditions. The noninteracting behavior of BBI was further confirmed by ITC, where the binding enthalpy of BBI to CMC was negligible compared with the high binding affinity (Kb) of KTI. This...

Details

ISSN :
15205118
Volume :
66
Issue :
17
Database :
OpenAIRE
Journal :
Journal of agricultural and food chemistry
Accession number :
edsair.doi.dedup.....893cf3c6fc38ff6ea20bec1cb6a6b390