ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Construction of starch-based bionic glutathione peroxidase and its catalytic mechanism

Rui-Rui Zhang, Shu-Fei Jiao, Zi-Jie Liu, Yun-Ying Zheng, Yan-Zhen Yin, Xing-Tang Liang, and Yong-Xian Liu

Guangxi Key Laboratory of Green Chemical Materials and Safety Technology, College of Petroleum and Chemical Engineering, Beibu Gulf University, Qinzhou, China

E-mail: jiaoshufei2013@163.com

Received: 13 October 2021  Accepted: 25 January 2022

Abstract:

Glutathione peroxidase (GPx) is an important selenium-containing antioxidant enzyme in human body. The preparation of bionic GPx and the mimicry of its catalytic behavior are of great significance for the development of antioxidant drugs. At present, most of the reported biomimetic selenoenzymes based on the macromolecular are difficult to be degraded, which restricts their applications in the fields such as medical treatment, health care, and functional food. In order to solve this issue, herein, the octenyl succinic acid-modified starch (OSA starch) prepared by the esterification of waxy corn starch was used as the raw material, a new selenium-functionalized starch (Se-starch) was synthesized via the reaction of OSA starch and sodium hydrogen selenide. Such Se-starch, as a biomimetic selenoenzyme, was characterized using ¹H NMR, EDS, XPS, SEM, XRD, and FT-IR. The Se-starch with a catalytic activity of 2.48 μM·min⁻¹ showed a typical catalysis behavior of saturated kinetic and enzymology. This catalytic activity is 1.04 × 10⁵ times higher than that of the PhSeSePh, a representative small molecule bionic GPx. The study of catalytic mechanism revealed that the octenyl succinate molecule bonded on the starch endowed it with hydrophobic micro-environments, which benefited the binding of hydrophobic substrates, and consequently increased the catalytic activity. This work not only provided a new idea for constructing natural polymers-based bionic GPx, but also offered an important theoretical basis for the development of new antioxidant drugs and functional foods.

Keywords: Glutathione peroxidase; OSA-modified starch; Artificial enzyme; Selenium modification; Catalytic mechanism

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-022-02104-4

Chemical Papers 76 (6) 3499–3506 (2022)