title: Structural stability and Sin a 1 anti-epitope antibody binding ability of yellow mustard (Sinapis alba L.) napin during industrial-scale myrosinase inactivation process.
abstract: This study investigated the structural stability of yellow mustard (YM, Sinapis alba L.) napin and the changes of its Sin a 1 anti-epitope antibody-binding ability during myrosinase enzyme inactivation process. The food industry uses myrosinase-inactive non-pungent YM for uses beyond spice applications. Napin was isolated from seeds received from an industrial processor before (YM + M) and after (YM - M) myrosinase inactivation. Secondary and tertiary structural features and surface hydrophobicity parameters of napin were analyzed. The Sin a 1 content in YM seeds and the stability of Sin a 1-containing napin during simulated in vitro gastrointestinal (GI) digestion were determined by a non-competitive indirect enzyme-linked immunosorbent assay using the Sin a 1 anti-epitope antibody (AE-Ab) as the primary Ab. YM napin retained the dominant alpha-helical components of secondary and tertiary structure folds during this process. YM - M napin showed changes in hydrophobicity parameters of the molecules and binding ability of AE-Ab: 2.19 ± 0.48 g per 100 g of YM - M seeds vs. 1.49 ± 0.16 g per 100 g YM + M seeds. YM - M proteins were more susceptible for in vitro GI digestion and also showed a 30% reduction in AE-Ab binding ability upon digestion of napins. This suggests that the myrosinase inactivation process has induced the surface modification of napin, exposing Sin a 1 epitope, leading to an increase in AE-Ab binding. However, the epitope region of YM - M napin showed improved susceptibility for hydrolysis during GI digestion resulting in fewer available epitope regions, suggesting a possible reduction in napin immune reactivity.
authors.affiliation: Agriculture and Agri-Food Canada, Saskatoon Research Centre, 107 Science Place, Saskatoon, SK S7N 0X2 Canada. Janitha.wanasundara@agr.gc.ca.
authors.forename: Harsha K
authors.initials: HK
authors.lastname: Marambe
authors.forename: Tara C
authors.initials: TC
authors.lastname: McIntosh
authors.forename: Bifang
authors.initials: B
authors.lastname: Cheng
authors.forename: Janitha P D
authors.initials: JP
authors.lastname: Wanasundara
mesh_terms: D055516:2S Albumins, Plant / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D000595:Amino Acid Sequence; D052179:Antigens, Plant / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D004789:Enzyme Activation; D000939:Epitopes / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D006026:Glycoside Hydrolases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010940:Plant Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D011485:Protein Binding; D012639:Seeds / Q000737:chemistry / Q000201:enzymology / Q000235:genetics / Q000378:metabolism; D031226:Sinapis / Q000737:chemistry / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism
chemical_list: D055516:2S Albumins, Plant; D052179:Antigens, Plant; D000939:Epitopes; D010940:Plant Proteins; C079479:Sin a I protein, Sinapis alba; D006026:Glycoside Hydrolases; C022739:thioglucosidase