Characterisation of histidine decarboxylase from Enterobacter and Lactococcus species.

Research Journal of Pharmaceutical, Biological and Chemical Sciences

article

Shlini P¹  Sneha Bhatt¹  Gletta Anjaly CT.¹ 

[1] Department of Biochemistry, Mount Carmel College

关键词: Histidine decarboxylase;    Enterobacterspp;    Lactococcus spp;    histamine;    Alizarine Red S;    zymogram;   

DOI  :  10.33887/rjpbcs/2019.10.6.1

学科分类：工程和技术（综合）

来源: Research Journal of Pharmaceutical, Biological and Chemical Sciences

【 摘 要 】

Histidine decarboxylase is a metabolic enzyme involved in the conversion of histidine to histamine.Histamine is a biologically active amine which can bring about a range of physiological effects. Even then, theenzyme histidine decarboxylase hasn’t been completely characterized due to its low availability and highinstability. The various histidine decarboxylases that have been isolated and studied provide contrastingresults with respect to the structure and involvement of coenzyme, adding to the complexity of the enzyme.The present study was carried out to isolate and purify histidine decarboxylase from the auxotrophic strains ofEnterobacterspp and Lactococcus spp. The organisms were cultured and characterized using biochemical testssuch as IMViC tests, catalase and oxidase test. The bacterial species was confirmed using these tests alongwithGram staining which indicated the presence of Gram-negative bacilli and Gram-positive cocci. Thestepwise purification of the enzyme involved ammonium sulphate precipitation followed by ion exchangechromatography and gel permeation chromatography. The activity of the enzyme was studied using aspectroscopic method wherein the product histamine, was made to react with Alizarine red S and Nickelsulphate in presence of acetate buffer. A zymogram was obtained to indicate the presence of the activeenzyme activity. The optimum pH and temperaturewere performed to obtain the optimum pH andtemperature along with pH and thermo stability. The pH optimum was found to be 7 and optimumtemperature was obtained at 47°C. The K and V were determined to be around 0.5 mM and 0.001 IUm max respectively. The enzyme was thus purified and studied for its activity and characteristics. This data obtainedwas further used to study enzyme inhibition which can prove a potential alternate to the side – effect drivenfourth generation of antihistamines.

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