Glycan characterisation and antioxidant activity of a novel N-linked glycoprotein from okra

Abstract

Glycoproteins are present in all living beings, and have many biological functions. The characterisation of glycan structures of plant glycoproteins has become increasingly important in biotechnology and agricultural applications. In the present work, the antioxidant activities of the okra glycoprotein were assessed. The glycan structures of the okra glycoprotein were analysed using lectin microarray combined with matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry. The okra glycoprotein showed relatively strong 2,2-diphenyl-1-picrylhydrazyl-scavenging ability and reducing power. In addition, the glycan structures of the okra glycoprotein mainly contained N-acetylglucosamine, mannose, and galactose. Furthermore, complex-type N-glycans were the major type of glycan structures from the okra glycoprotein. Most of the complex N-glycans of the okra glycoprotein had terminal GalNAc and Gal N-glycan structures; the glycoprotein showed a high level of fucosylated complex-type glycans. Therefore, the okra glycoprotein is a promising antioxidant. Results of the present work might serve as a reference for a better understanding of the structural information and bioactivity of okra glycoprotein.