Recent advances in the application of microbial diamine oxidases and other histamine-oxidizing enzymes

Abstract

The consumption of foods fraught with histamine can lead to various allergy-like symptoms if the histamine is not sufficiently degraded in the human body. The degradation occurs primarily in the small intestine, naturally catalyzed by the human diamine oxidase (DAO). An inherent or acquired deficiency in human DAO function causes the accumulation of histamine and subsequent intrusion of histamine into the bloodstream. The histamine exerts its effects acting on different histamine receptors all over the body but also directly in the intestinal lumen. The inability to degrade sufficient amounts of dietary histamine is known as the ‘histamine intolerance’. It would be preferable to solve this problem initially by the production of histamine-free or -reduced foods and by the oral supplementation of exogenous DAO supporting the human DAO in the small intestine. For the latter, DAOs from mammalian, herbal and microbial sources may be applicable. Microbial DAOs seem to be the most promising choice due to their possibility of an efficient biotechnological production in suitable microbial hosts. However, their biochemical properties, such as activity and stability under process conditions and substrate selectivity, play important roles for their successful application. This review deals with the advances and challenges of DAOs and other histamine-oxidizing enzymes for their potential application as processing aids for the production of histamine-reduced foods or as orally administered adjuvants to humans who have been eating food fraught with histamine.

Novel Archaeal Histamine Oxidase from Natronobeatus ordinarius: Insights into Histamine Degradation for Enhancing Food Safety

“…33 A majority of the characterized HODs were purified from their native producing strains with a low productivity. 7 Their expression is induced by histamine. 34 In this study, HOD was heterologously expressed in a haloarchaeal host under the control of a strong constitutive P.phaR promoter 25 and then purified with affinity chromatography.…”

“…Most of the characterized copper-containing amine oxidases were monomers or dimers. 7 The copper-containing amine oxidase from Mycobacterium sp. JC1 existed as both dimers and tetramers, exhibiting nearly identical biochemical properties, including subunit size, optimal temperature and pH, substrate specificities, and K m value.…”

“…12 Generally, the microbial HODs reported show mesophilic properties, mostly within the range of 40−45 °C. 7 HOD Nbs displayed a relatively high optimum temperature. Compared with other microbial HODs, HOD Nbs was a slightly thermophilic enzyme.…”

“…39 In contrast, many microbial HODs exhibited a narrow substrate scope, mainly limited to histamine and tyramine. 7 For example, the crude HOD from Glutamicibacter sp. N1A3101 demonstrated high oxidase activity toward histamine, with a low activity toward tyramine.…”

“…6 Histamine-degrading enzymes are thus highly demanded for the manufacturing of histamine-reduced foods. 7 Diamine oxidases (EC 1.4.3.22), primary amine oxidases (EC 1.4.3.21), and monoamine oxidases (EC 1.4.3.4) can all catalyze the oxidative deamination of histamine. 8 These three enzyme classes are primarily distinguished by their substrate preferences and cofactors.…”