Combined effect of temperature and pH on the structure and IgE-reactivity of Arginine Kinase from the edible insect Hermetia illucens

• High temperature affects structural stability of the allergen Arginine Kinase from H. illlucens . • Arginine kinase is more prone to fragmentation at acidic pH both at low and high temperature. • Heat treatments have the potential to reduce Arginine Kinase IgE cross-reactivity. Insects are a good alternative source of proteins and other nutrients for human nutrition. In view of their possible use in the human diet in the western world, it is essential to investigate the safety risks for allergic consumers. Arginine kinase (AK), which is involved in the process of ATP homeostasis in invertebrates, has recently been identified in the edible insect Hermetia illucens as a potential allergen capable of cross-reactivity with orthologous proteins of mites and shrimps. Herein, we studied the protein stability and IgE-reactivity when AK is exposed to increasing temperatures or stored at low temperatures under varying pH conditions. AK incubation at high temperatures under neutral, basic and acidic conditions, can induce structural destabilization, aggregation or fragmentation often resulting in reduced IgE reactivity. While AK degradation occurs more rapidly at acidic pH, this protein fragmentation does not always correlate with a reduction in IgE-reactivity. This study reveals the complex interplay between temperature and pH in influencing the structural stability and the IgE-reactivity of the Arginine Kinase from the edible insect Hermetia illucens .