Bacterial histidine decarboxylase

Relationship of Bacterial Histidine Decarboxylase Production to Histamine Formation. Many studies have been completed with the objective of understanding factors such as storage time and temperature that influence production of histamine in fish. The majority of the investigations have considered only the histamine content of the product, and, consequently, only limited information is available concerning the relationship of histidine decarboxylase formation by the microflora to histamine build-up. 

While the carbon dioxide produced by decarboxylation of histidine can be measured by the standard Warburg manometer technique, the utility of the method is severely limited by the very small degree to which decarboxylation occurs with most mammalian histidine decarboxylase preparations even at high substrate concentrations. In practice, only bacterial histidine decarboxylases have proved sufficiently active to be measured conveniently by the manometric method . Small amounts of carbon dioxide can, however, be determined by the sensitive micro-diffusion technique of Conway , and this has been used successfully for measuring the activity of mammalian histidine decarboxylases . 

Bacterial histidine decarboxylase (EC 4.1.1.22) is unique among bacterial amino acid decarboxylases in not requiring PEP. Mammalian histidine decarboxylase does have a PEP requirement. Battersby et al. (298, 299)... 

The principal pathways for the biogenesis and metabolism of histamine are well known. Histamine is formed by decarboxylation of the amino acid, L-histidine, a reaction catalyzed by the enzyme, histidine decarboxylase. This decarboxylase is found in both mammalian and non-mammalian species. The mammalian enzyme requires pyridoxal phosphate as a cofactor. The bacterial enzyme has a different pH optimum and utilizes pyruvate as a cofactor (26.27). 

Amine build-up in fish muscle usually results from decarboxylation of amino acids in the muscle by enzymes of bacterial origin. This review will present information on the activity of bacterial decarboxylases and the formation of amines in fish. Mechanisms of decarboxylase action and production of bacterial decarboxylases in fish muscle are discussed. Emphasis is placed upon studies dealing with formation of histidine decarboxylase and histamine. Histamine, because of its involvement in Scombroid food poisoning, has been extensively studied with regard to its formation in fish and fishery products. 

Because amine formation in fish muscle and other foods usually results from bacterial growth with concomitant production of a bacterial decarboxylase, this paper will concentrate on the mechanisms of bacterial decarboxylation and factors influencing the production and activity of the enzymes. Also, because of the overall scope of the subject, the availability of excellent reviews on bacterial decarboxylation (2, 3) and the public health importance of histamine in fish and fishery products, this paper will primarily be limited to a discussion of histidine decarboxylase (EC 4.1.1.22) and the formation of histamine in fish muscle. 

Pyruvoyl cofactor is derived from the posttranslational modification of an internal amino acid residue, and it does not equilibrate with exogenous pyruvate. Enzymes that possess this cofactor play an important role in the metabolism of biologically important amines from bacterial and eukaryotic sources. These enzymes include aspartate decarboxylase, arginine decarboxylase," phosphatidylserine decarboxylase, . S-adenosylmethionine decarboxylase, histidine decarboxylase, glycine reductase, and proline reductase. ... 

As is the case for most enzyme activities measured in vitro, there is some doubt whether the histidine decarboxylase activities determined as above in various organs truly reflect the contribution of these organs to histidine decarboxylation in the intact animal. In vivo measurements give an overall picture of histidine decarboxylation in the living animal, but they can give little indication of the contribution made by individual organs. Moreover, the interpretation of such measurements is rendered difficult by bacterial decarboxylation of histidine in the gut, by metabolic destruction of histamine, and by the release of histamine from storage sites. Nevertheless, such measurements have provided much useful information, and they are particularly suited to the study of the effectiveness of histidine decarboxylase inhibitors in intact animals. As with in vitro methods the in vivo measurements can, in theory, be made either on the carbon dioxide or on the histamine formed in the decarboxylation. 

HTP and DOPA decarboxylase activities of partially purified extracts of hog kidney it has been stated that these compounds do not also inhibit histidine decarboxylase. This statement is misleading, however, as it refers to results obtained by earlier workers using a histidine decarboxylase of bacterial origin . ... 

Histamine appears during fermentation, irrespective of the yeast strain used, and concentrations increase during malolactic fermentation. There is, however, no correlation between the histidine content in the must and the histamine concentration in the wine. Although wines generally only contain a few mg/1, concentrations in certain wines may exceed the 10 mg/1 maximum value prescribed by legislation in some countries. The exact causes and the conditions responsible for the formation of large quantities of histamine in wine are not very well known. The most probable explanation is that this is due to the action of specific bacterial strains with a high histidine decarboxylase content (Volume 1, Section 5.4.2). 

Holland et al. (1978) suggested that a second enzyme may be required for histamine synthesis and/or stability (histidine decarboxylase was shown to be unstable). Histamine production can have a significant effect on the course of acne vulgaris. If the pH inside the follicle drops to 4.5, approaching the first pH-optimum, histamine production in vivo will increase, serving as a metabolic response to the bacterial environment since amines reduce the acidity, histamine production creates more favorable... 

THE SUBSTRATE SPECIFICITY OF HISTIDINE DECARBOXYLASES For many years two main types of histidine decarboxylase were recognized, one of bacterial origin with its optimum activity at pH the other,... 

Histidine (bacterial) S-Adenosylmethionine Aspartate a- decarboxylase (3-Alanine... 

Gale studied the formation of bacterial decarboxylases for arginine, lysine, ornithine, histidine, tyrosine, and glutamic acid. One result of his studies was the demonstration that these enzymes occur in variable amounts in the cells and that environmental conditions, such as pH of the medium, influence the amount of enzyme formed. The failure to... 

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