ARG I is one of the

ARG I is one of the most important mammalian enzymes responsible for nitrogen metabolism since it comprises the main route for the elimination of excess nitrogen resulting from amino Efavirenz and nucleotide metabolism [18]. ARG I deficiency leads to hyperargininemia, characterized by progressive neurological and intellectual impairment, persistent growth retardation and infrequent episodes of hyperammonemia [19]. ARG I and ARG II possess the same catalytic function but differ with respect to tissue distribution, cellular localization, metabolic function, physicochemical and kinetic properties and immunological cross reactivity [4], [20]. Arginases from eukaryotes have been under extensive study because they have important biological functions and are associated with a variety of diseases, such as diabetes [20], cardiovascular disorders and cancer progression [13], [21]. Arginase, a powerful anticancer enzyme, has been studied in vitro to treat several types of cancer, such as breast, rectal, and colon, to depletes blood L-arginine levels in order to starving cancer cells that are auxotrophic to L-arginine amino acid and argininosuccinate synthase-expressing tumors [22]. Many studies have shown that the increased stimulation of arginase expression in animal metabolism leads to the production of polyamines, which helps to stop tumor cell proliferation and wound healing [23].
Materials and methods
Results
Discussion Arginases are ubiquitous in nature, having been found in bacteria, fungi, plants, and mammals [4]. In mammals, arginase has been detected in many different tissues having complete and incomplete urea cycle, such as liver, kidney and mammary gland [34]. Aminlari and Vaseghi [35] reported that the liver was the richest source of arginase in most of domestic animals. However, there is no information about the purification and the properties of this enzyme in camel, the current study was designed to set up a simple scheme to purify arginase from camel liver cytosol and compare its molecular and kinetic properties with that were reported from other species. In the present investigation, the purification procedure permitted us to obtain a highly purified enzyme preparation. The overall yield of purified CL-ARG being almost 6.1% with a final specific activity of 18485 units/mg protein. β-Mercaptoethanol was used in all the purification steps to prevent the oxidation of the native enzyme during purification and thus decreasing the formation of multiple active forms [36]. Harell and Sokolovsky [37] purified the beef liver arginase to a homogenous state of 10.2% yield with a specific activity of 790 units/mg protein using heat treatment, acetone fractionation, DEAE-cellulose column chromatography, molecular sieving and isoelectric focusing. Also, Dabir et al. [25] purified buffalo liver arginase to a homogenous state with a yield of 18.3% using heat treatment, ammonium sulphate fractionation, DEAE-cellulose column chromatography, molecular sieving and affinity chromatography. The purified CL-ARG preparation gave a single diffuse protein band that migrated towards the anode throughout native PAGE at pH 8.8. The anionic behaviour in electrophoresis relates the camel liver enzyme to human, rabbit, horse, calf and pig liver arginases [36]. The native molecular weight of purified CL-ARG was determined by size-sieving chromatography. Sephadex G 100-120 gel filtration column revealed that CL-ARG exhibited a molecular weight about 180kDa. The sedimentation and diffusion studies carried out by Hirsch-kolb et al. [38] with high purified beef liver arginase suggested a molecular weight between 120 and 140kDa. Molecular weights in the range from 120 to 160kDa obtained for ureotelic liver arginases differ remarkably from the molecular weights recorded for uricotelic and fungal arginases (lizard liver arginase molecular weight equals 276kDa and arginase from Neurospora crassa has a molecular weight of 278kDa), which seems to be twice higher [39], [40]. Using SDS-PAGE, resolution of purified CL-ARG exhibited a single band corresponding to apparent molecular weights of 35kDa, indicating its oligomeric structure. Jenkinson et al. [3] showed that the subunit molecular masses for mammalian arginases vary between about 30kDa and 40kDa. Arginase from lizard and chicken livers has a molecular weight of about 280kDa which represents an association of two tetramers to form an octamer [40]. The molecular weight of earth warm gut arginase was estimated to be 27kDa, which represents a monomer arginase [41].