Arginine deiminase

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Arginine deiminase
Arginine deiminase
Ribbon model of the arginine deiminase from P. aeruginosa , according to PDB  1RXX
other names
  • L -arginine imino hydrolase
  • Arginine dihydrolase (ADH)
  • Citrulline iminase

Available structural data : 4BOF , 2CMU , 2A9G , 2AAF , 2ABR , 2ACI , 1S9R , 1LXY

Identifier
External IDs
Enzyme classification
EC, category 3.5.3.6 ,  hydrolase
Response type hydrolysis
Substrate L- arginine + H 2 O
Products L - (+) - citrulline + NH 3
Occurrence
Parent taxon Bacteria , eukaryotes

Arginine Deiminase ( ADI ) is an enzyme that is mainly found in bacteria and eukaryotes . The arginine deiminase catalyzes the first step of the arginine deaminase metabolic pathway (also known as the arginine dihydrolase metabolic pathway ), which is necessary for the production of adenosine triphosphate (ATP) and the acid-base balance of bacteria and is used as a survival strategy for certain bacteria has developed.

Arginine Deiminase Metabolic Pathway

The arginine deiminase metabolic pathway is a catabolic metabolic pathway that has been investigated in various bacteria, for example in lactic acid bacteria , mycoplasma , halobacteria , Pseudomonas spp. and Bacillus spp. In this case, L -arginine ( 1 ) via the arginine / ornithine antiporter introduced (A / O AP) in the metabolic pathway. L -arginine is initially by the enzyme arginine deiminase to L - citrulline - (+) ( 2 ) and ammonia hydrolyzed . The L - (+) - citrulline is then converted to L - (+) - ornithine ( 3 ) by cleavage of the aminocarbonyl residue by means of the enzyme ornithine transcarbamylase (OTC ) and subsequent phosphorylation of the aminocarbonyl residue to carbamoyl phosphate ( 4 ). Then carbamoyl phosphate is converted to ammonia and carbon dioxide by the enzyme carbamate kinase (CK) with the formation of ATP . The L - (+) - ornithine formed leaves the metabolic pathway via the same antiporter.

This metabolic pathway is particularly used when there is a lack of oxygen or, to a lesser extent, when all carbon or other energy sources have been used up. The metabolic pathway is controlled by catabolite repression . If energetically cheaper products are available in significant quantities, the genes of catabolic enzymes are regulated in such a way that the production of these enzymes is inhibited. Furthermore, the metabolic pathway influences the acid-base balance of various bacteria. In the case of acid stress, glycolysis and the growth of bacteria are inhibited. Bacteria can recover from acid stress caused by the ammonia produced in the metabolic pathway and the resulting increase in pH . This enables the bacteria to survive and further acid to accumulate without acid stress occurring.

Arginine deiminase pathway.svg

Detection of the bacterial enzyme

Since the arginine deiminase pathway occurs in numerous types of bacteria, it is used to differentiate and determine them . In the microbiological specialist literature, the detection of the two first-mentioned enzymes is summarized as arginine dihydrolase (ADH) and includes the conversion of L- arginine ( 1 ) via L- citrulline ( 2 ) to L- ornithine ( 3 ), with the elimination of ammonia (cf. Metabolic scheme). The detection of arginine dihydrolase in representatives of the gram-negative enterobacteria is used for characterization and is part of a colored series to determine the genus or species . The test procedure was introduced in 1955 and has been part of miniaturized test systems since the 1970s (e.g. in the API 20 E system).

For the detection of bacterial arginine dihydrolase, the standardized, arginine-containing nutrient medium is inoculated with bacterial material and incubated . The incubation should take place under anoxic conditions, in order to prevent the entry of oxygen into the test tube, the inoculated mixture is covered with paraffin oil. The formation of ornithine and ammonia increases the pH value in the test medium; the evaluation is based on the color change of the pH indicator integrated in the nutrient medium . Phenol red is mostly used; an incubation period of 18 to 24 hours should be observed before the ADH reaction is assessed. A method using thin layer chromatography is described as a faster variant : the liquid nutrient medium containing arginine (pH 5.5) is incubated for one hour after inoculation, centrifuged and the supernatant is mixed with dansyl chloride and incubated for a further hour. After another centrifugation, the supernatant can be examined with the aid of two-dimensional thin-layer chromatography, the reaction products of arginine dihydrolase reacted with dansyl chloride are detected by their fluorescence .

The detection of the bacterial arginine dihydrolase is important for the differentiation of the enterobacteria. Representatives of the genera Enterobacter , Cronobacter and Cedecea have this enzyme, as do serovars of Salmonella enterica subsp. arizonae and the species Plesiomonas shigelloides . In contrast, representatives of the genera Escherichia , Klebsiella (including Klebsiella aerogenes ), Morganella , Pantoea , Proteus , Providencia , Raoultella , Serratia , Shigella and Yersinia are ADH-negative. Within the genera Salmonella as well as Citrobacter there are ADH-positive and -negative representatives, which the detection of the arginine dihydrolase reaction helps to distinguish.

Examples of further gammaproteobacteria which are of medical importance and which have arginine dihydrolase are some species from the Vibrionaceae family , for example Vibrio fluvialis and Photobacterium damselae . The genera Aeromonas and Pseudomonas (Gammaproteobacteria) are also ADH-positive, while the ADH-positive species Chromobacterium violaceum belongs to the Betaproteobacteria . The bacteria mentioned are relevant for medical microbiology, are partly listed in the group “ non-fermenting gram-negative rods” and can then be identified with the API 20 NE system, for example.

Individual evidence

  1. ↑ UniProtKB results. In: UniProtKB. Accessed December 31, 2019 .
  2. ^ A b Jon J. Kabara: Preservative-Free and Self-Preserving Cosmetics and Drugs: Principles and Practices . CRC Press, 1997, ISBN 978-0-8247-9366-1 , pp. 27–28 ( limited preview in Google Book search).
  3. ↑ a b c Roland Süßmuth, Jürgen Eberspächer, Rainer Haag, Wolfgang Springer: Biochemical-microbiological internship . 1st edition. Thieme Verlag, Stuttgart / New York 1987, ISBN 3-13-685901-4 , p. 78-85 .
  4. ↑ a b c K. C. Chen, NJ Culbertson, JS Knapp, GE Kenny, KK Holmes: Rapid method for simultaneous detection of the arginine dihydrolase system and amino acid decarboxylases in microorganisms . In: Journal of Clinical Microbiology . tape 16 , no. 5 November 1982, pp. 909-919 , PMID 7153341 , PMC 272502 (free full text).
  5. ↑ a b J. J. Farmer III, BR Davis u. a .: Biochemical identification of new species and biogroups of Enterobacteriaceae isolated from clinical specimens . In: Journal of Clinical Microbiology . tape 21 , no. 1 , January 1985, p. 46-76 , PMID 3881471 , PMC 271578 (free full text).
  6. ^ Vagn Møller: Simplified tests for some amino acid decarboxylases and for the arginine dihydrolase system . In: Acta pathologica et microbiologica Scandinavica . tape 36 , no. 2 , 1955, pp. 158-172 , doi : 10.1111 / j.1699-0463.1955.tb04583.x , PMID 14375937 .
  7. ↑ a b P. B. Smith, KM Tomfohrde, DL Rhoden, A. Balows: API system: a multitube micromethod for identification of Enterobacteriaceae . In: Applied Microbiology . tape 24 , no. 3 , September 1972, p. 449-452 , PMID 4562482 , PMC 376540 (free full text).
  8. ↑ System for the identification of Enterobacteriaceae and other gram-negative, non-demanding rods . In: bioMérieux sa (ed.): Operating instructions api® 20 E API, REF 20 100/20 160 . May 2004, p. 1-5 .
  9. ^ Species identifiable by the various identification systems . In: bioMérieux sa (ed.): API & ID 32 Identification Databases . April 2015 ( biomerieux.de ).