Diamino oxidase (DAO)-enriched extracts from germinated yellow pea (Pisum sativum L.) for histamine degradation

Diamine oxidase (DAO; EC 1.4.3.22) is the main enzyme responsible for breaking down dietary histamine, and its deficiency can lead to histamine intolerance. Management of this condition typically involves a low-histamine diet and oral DAO supplementation. Porcine kidney DAO is widely used as a supplement; however, DAO formulations from animal sources exhibit relatively low specific enzyme activity. Plant-based DAO from germinated legumes has been proposed as an alternative with potentially higher enzymatic activity. This study aimed to develop a functional DAO-enriched extract from yellow peas ( Pisum sativum L. ). Using a DAO extract from freeze-dried 6-day-germinated seeds exhibiting a specific enzyme activity of 102 ± 6 mU/mg protein, two independent strategies were applied to identify the most effective approach for generating preparations with higher specific enzymatic activity. Subsequent dialysis and ultrafiltration of the extract using a 50 kDa cutoff membrane yielded samples with a specific activity of 200 ± 20 mU/mg of protein. In contrast, ammonium sulfate precipitation, size-exclusion chromatography, and ion-exchange chromatography yielded samples with a higher specific activity of 880 ± 20 mU/mg protein (almost 9-fold higher than the crude extract). These findings suggest that DAO-enriched extracts can be obtained from yellow peas, which may support their potential use in the management of histamine intolerance.