TY - JOUR
T1 - In-flow SAXS investigation of whey protein isolate hydrolyzed by bromelain
AU - Li, Jiecheng
AU - Yang, Zhi
AU - Lin, Xiaoling
AU - Wu, Sinong
AU - Li, Guantian
AU - Li, Na
AU - Otter, Don
AU - Zhu, Fan
AU - Hartinger, Christian
AU - Corke, Harold
AU - Hemar, Yacine
N1 - Publisher Copyright:
© 2021 Elsevier B.V.
PY - 2021/12/20
Y1 - 2021/12/20
N2 - In-flow small angle X-ray scattering (SAXS) was used to probe in real-time (typically every second) the hydrolysis of whey protein isolate (WPI) by bromelain. The WPI concentration was 2.5%, the enzyme to substrate ratio was 1:10, and the enzymatic reaction was followed for 90 min at 50 °C and pH 7. SAXS showed that the average size of WPI molecules was about 20 Å and that even at the completion of the enzymatic reaction some intact molecules of similar size remained; these are likely bromelain molecules and trace amount of BSA. SAXS allowed us to monitor the hydrolysis course through the calculation of the power-law exponent (P) and the Guinier scale factor (G) using a theoretical unified model fitting. The fitting exercise also indicated that bromelain hydrolysis transforms the globular WPI molecules into Gaussian polypeptides. The hydrolysis of WPI, which was completed within 40 min of hydrolysis, was confirmed by the degree of hydrolysis and turbidity measurements and by SDS-PAGE, which showed that bromelain has a broad specificity. This study demonstrates that SAXS is a powerful method to monitor in situ and real-time protein hydrolysis and can offer insights into protein structural changes that occur.
AB - In-flow small angle X-ray scattering (SAXS) was used to probe in real-time (typically every second) the hydrolysis of whey protein isolate (WPI) by bromelain. The WPI concentration was 2.5%, the enzyme to substrate ratio was 1:10, and the enzymatic reaction was followed for 90 min at 50 °C and pH 7. SAXS showed that the average size of WPI molecules was about 20 Å and that even at the completion of the enzymatic reaction some intact molecules of similar size remained; these are likely bromelain molecules and trace amount of BSA. SAXS allowed us to monitor the hydrolysis course through the calculation of the power-law exponent (P) and the Guinier scale factor (G) using a theoretical unified model fitting. The fitting exercise also indicated that bromelain hydrolysis transforms the globular WPI molecules into Gaussian polypeptides. The hydrolysis of WPI, which was completed within 40 min of hydrolysis, was confirmed by the degree of hydrolysis and turbidity measurements and by SDS-PAGE, which showed that bromelain has a broad specificity. This study demonstrates that SAXS is a powerful method to monitor in situ and real-time protein hydrolysis and can offer insights into protein structural changes that occur.
KW - Bromelain
KW - Enzymatic hydrolysis
KW - SAXS
KW - Whey protein isolate
UR - http://www.scopus.com/inward/record.url?scp=85116561626&partnerID=8YFLogxK
U2 - 10.1016/j.colsurfa.2021.127662
DO - 10.1016/j.colsurfa.2021.127662
M3 - 文章
AN - SCOPUS:85116561626
SN - 0927-7757
VL - 631
JO - Colloids and Surfaces A: Physicochemical and Engineering Aspects
JF - Colloids and Surfaces A: Physicochemical and Engineering Aspects
M1 - 127662
ER -