l-Glutaminase has gained an important attention as glutamine-depleting enzyme in treatment of various cancers. Therefore, this study aimed to purify, characterize and investigate antitumor activity of l-glutaminase from camel liver mitochondria (CL-Glu), since no available information about CL-Glu from camel. CL-Glu was purified using cell fractionation, ultrafiltration, DEAE-and CM-cellulose chromatography columns. The purified CL-Glu was a monomer with a molecular weight of 70 ± 3 kDa, isoelectric point of 7.2, optimum temperature of 70 °C and it was active over a broad pH range with a pH optimum at pH 8.0. Its activity had a clear dependence on phosphate ions. The studied enzyme showed sigmoidal kinetics, indicated its allosteric behavior with Km of 36 ± 4 mM and Hill coefficient of 1.5 which suggested a positive cooperatively of active sites. The purified l-glutaminase exerted antitumor activity against different cell lines with the highest cytotoxic activity against Hepatocellular carcinoma cell line (HepG-2) with an IC50 value of 152 µg/ml. In conclusion, l-glutaminase was purified from camel liver using simple methods and its unique properties such as stability at both wide pH range and at high temperature along with its relatively low molecular weight, facilitated its usage in medical applications as antitumor drug.
Keywords: Antitumor activity; Camel liver; Characterization; Glutaminase; Hepatocellular carcinoma; Purification.
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