Urea cycle of Fasciola gigantica: Purification and characterization of arginase

Mohamed, Saleh A.; Fahmy, Afaf S.; Mohamed, Tarek M.; Hamdy, Soha M.

doi:10.1016/j.cbpb.2005.08.002

Cited by 23 publications

(27 citation statements)

References 62 publications

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“…Recently, arginase has been isolated and characterised from the trematode parasite F. gigantica (Mohamed et al, 2005). There was also some evidence reported for arginase activity in S. mansoni some 40 years ago (Senft, 1966) and the NCBI protein database contains a sequence for an arginase-ortholog in S. japonicum (AAQ16108).…”

Section: Resultsmentioning

confidence: 99%

“…Branched-chain amino acids such as l -lysine inhibit both human arginases (Carvajal and Cederbaum, 1986; Fuentes et al, 1994a; Colleluori et al, 2001) and F. gigantica arginase (Mohamed et al, 2005). Surprisingly, we found that l -lysine and diaminopimelic acid, a precursor for l -lysine inhibiting liver arginase from guinea pig (Soler et al, 1981), failed to block SmARG activity.…”

Section: Resultsmentioning

confidence: 99%

“…Arginase from F. gigantica is also sensitive to replacement of Mn 2+ by other bivalent metal cations. Here cation replacement with Mg 2+ , Ca 2+ and Co 2+ reduced the enzymatic activity when compared with Mn 2+ (Mohamed et al, 2005). …”

Section: Resultsmentioning

confidence: 99%

“…This could include energy metabolism, osmosis, cell proliferation, extracellular matrix production (Jenkinson et al, 1996), nitrogen metabolism as in F. gigantica (Mohamed et al, 2005) or controlling the dilatation of parasitised blood vessels by reducing the production of NO from endothelial NOS-3 (Berkowitz et al, 2003). …”

Section: Discussionmentioning

confidence: 99%

“…Urea can also regulate osmosis (Yancey et al, 1982). Recently, an arginase family member was identified and characterised in the trematode parasite Fasciola gigantica (Mohamed et al, 2005), a close relative of schistosomes. Here, the enzyme seems to be essential for nitrogen metabolism.…”

Section: Introductionmentioning

confidence: 99%

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Schistosoma mansoni arginase shares functional similarities with human orthologs but depends upon disulphide bridges for enzymatic activity

Fitzpatrick

Fuentes

Chalmers

et al. 2009

International Journal for Parasitology

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Schistosome helminths constitute a major health risk for the human population in many tropical areas. We demonstrate for the first time that several developmental stages of the human parasite Schistosoma mansoni express arginase, which is responsible for the hydrolysis of L-arginine to Lornithine and urea. Arginase activity by alternatively activated macrophages is an essential component of the mammalian host response in schistosomiasis. However, it has not been previously shown that the parasite also expresses arginase when it is in contact with the mammalian host. After cloning and sequencing the cDNA encoding the parasite enzyme, we found that many structural features of human arginase are well conserved in the parasite ortholog. Subsequently, we discovered that S. mansoni arginase shares many similar molecular, biochemical and functional properties with both human arginase isoforms. Nevertheless, our data also reveal striking differences between human and schistosome arginase. Particularly, we found evidence that schistosome arginase activity depends upon disulphide bonds by cysteines, in contrast to human arginase. In conclusion, we report that S. mansoni arginase is well adapted to the physiological conditions that exist in the human host.

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Section: Resultsmentioning

confidence: 99%