Influence of sodium alginate pretreated by ultrasound on papain properties: Activity,structure, conformation and molecular weight and distribution |
| |
| Institution: | 1. Department of Chemistry, Faculty of Science, Azarbaijan Shahid Madani University, Tabriz, Iran;2. Department of Biology, Faculty of Science, Azarbaijan Shahid Madani University, Tabriz, Iran;1. College of Biosystems Engineering and Food Science, Zhejiang University, Hangzhou 310058, China;2. National Engineering Laboratory of Intelligent Food Technology and Equipment, Hangzhou 310058, China;3. Zhejiang Key Laboratory for Agro-Food Processing, Hangzhou 310058, China;4. Fuli Institute of Food Science, Zhejiang University, Hangzhou 310058, China;1. Institute of Biochemistry and Biophysics, University of Tehran, Tehran, Iran;2. Polymer Division, School of Chemistry, College of Science, University of Tehran, Tehran, Iran;3. Department of Radiobiology, Tehran University of Medical Sciences, Tehran, Iran;1. Departament of Chemistry, Federal University of Piauí, Teresina, Piauí, Brazil;2. Department of Biophysics and Physiology, Federal University of Piauí, Teresina, Piauí, Brazil;3. Department of Fashion Design, Federal University of Piauí, Teresina, Piauí, Brazil;4. Center for Textile Science and Technology, University of Minho, Guimarães, Portugal;5. Department of Biochemistry and Pharmacology, Federal University of Piauí, Teresina, Piauí, Brazil;6. Department of Veterinary Morphophysiology, Federal University of Piauí, Teresina, Piauí, Brazil |
| |
| Abstract: | The aim of the study was to investigate the impact of sodium alginate (ALG) pretreated by ultrasound on the enzyme activity, structure, conformation and molecular weight and distribution of papain. ALG solutions were pretreated with ultrasound at varying power (0.05, 0.15, 0.25, 0.35, 0.45 W/cm2), 135 kHz, 50 °C for 20 min. The maximum relative activity of papain increased by 10.53% when mixed with ALG pretreated by ultrasound at 0.25 W/cm2, compared with the untreated ALG. The influence of ultrasound pretreated ALG on the conformation and secondary structure of papain were assessed by fluorescence spectroscopy and circular dichroism spectroscopy. The fluorescence spectra revealed that ultrasound pretreated ALG increased the number of tryptophan on papain surface, especially at 0.25 W/cm2. It indicated that ultrasound pretreatment induced molecular unfolding, causing the exposure of more hydrophobic groups and regions from inside to the outside of the papain molecules. Furthermore, ultrasound pretreated ALG resulted in minor changes in the secondary structure of the papain. The content of α-helix was slightly increased after ultrasound pretreatment and no significant change was observed at different ultrasound powers. ALG pretreated by ultrasound enhanced the stability of the secondary structure of papain, especially at 0.25 W/cm2. The free sulfhydryl (SH) content of papain was slightly increased and then decreased with the increase of ultrasonic power. The maximum content of free SH was observed at 0.25 W/cm2, under which the content of the free SH increased by 6.36% compared with the untreated ALG. Dynamic light scattering showed that the effect of ultrasound treatment was mainly the homogenization of the ALG particles in the mixed dispersion. The gel permeation chromatography coupled with the multi-angle laser light scattering photometer analysis showed that the molecular weight (Mw) of papain/ALG was decreased and then increased with the ultrasonic pretreatment. Results demonstrated that the activity of immobilized papain improved by ultrasonic pretreatment was mainly caused by the variation of the conformation of papain and the effect of interactions between papain and ALG. This study is important to explain the intermolecular interactions of biopolymers and the mechanism of enzyme immobilization treated by ultrasound in improving the enzymatic activity. As expected, ALG pretreated by appropriate ultrasound is promising as a bioactive compound carrier in the field of immobilized enzyme. |
| |
| Keywords: | Ultrasound pretreated sodium alginate Papain Activity Conformation Intermolecular interactions |
| 本文献已被 ScienceDirect 等数据库收录！ |
|
