J Pure Appl Microbiol | Research Article | Volume 12, Issue 4 | Article Number: 5284

Sahar W. M. Hassan1*, Aida M. Farag2 and Ehab A. Beltagy1

1Marine Microbiology Laboratory, National Institute of Oceanography and Fisheries, Alexandria, Egypt.
2Marine Biotechnology and Natural Products Extract Laboratory, National Institute of Oceanography and Fisheries, Alexandria, Egypt.

Corresponding Author E-mail: saharwefky@yahoo.com
Received: 20/08/2018| Accepted: 09/10/2018 |Published: 31/12/2018
DOI: http://dx.doi.org/10.22207/JPAM.12.4.19

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ABSTRACT

L-asparaginase (E.C.3.5.1.1) is an enzyme responsible for hydrolysis of L-asparagine into aspartic acid and ammonia, and has its significant applications in the therapeutics and food technology. It was produced by the marine Aspergillus terreus and precipitated by 65% ammonium sulphate, followed by purification using gel filtration on Sephadex G-100 and DEAE-cellulose ion exchange chromatography, which yielded 11.96 fold purification. The molecular weight of the purified L-asparaginase was approximately 85 kDa, determined by a sodium dodecyl sulphate polyacrylamide gel electrophoresis. L-asparaginase showed high affinity for L-asparagine with a Km of 31.5 mM and Vmax of 500 U/ml. The optimum pH and temperature of the purified enzyme were 5.8 and 40 oC, respectively. The L-asparaginase enzyme was stable from pH 4 to 5.8 and stable up to 70 oC. The effect of activators and inhibitors was studied providing that CdCl2, Pb Cl2, and Hg Cl2 strongly inhibited the enzyme activity, while Na Cl highly enhanced activity. Anticancer activity of the purified L-asparaginase was detected against HCT-116, Hep-G2 and MCF-7 cell lines with IC50 ranged from 3.79-12.6 µg/ml.


Keywords: 
L-asparaginase, Aspergillus terreus, purification, characterization, anticancer activity.