Mia Angela N. Judicpa Prince Henry S. Segura (March 2011)
Philippine Science High School Western Visayas Campus – Department of Science and Technology (DOST-PSHS WVC), Brgy. Bito-on, Jaro, Iloilo City 5000, Philippines
ABSTRACT
L-asparaginase, an antineoplastic enzyme that does not occur naturally in the human body, depletes the nonessential amino acid asparagine which is essential for the growth and proliferation of tumor cells. L-asparaginase enzyme from Escherichia coli has been proven effective in treating leukemia (particularly Acute Lymphoblastic Leukemia) and it is being modified in order to achieve higher levels of enzyme activity. One such modification in bacteria is the addition of thiol compounds which has been proven to drastically increase activity in Erwinia carotovora. This study was performed in order to measure and compare the activity of 1-asparaginase (mol/mg ammonia released) from Escherichia coli with the presence and absence of thiol compounds L-cysteine and reduced Glutathione. The local E. coli strain, E. coli atce 25922, was grown in M9 liquid media. To obtain the crude enzyme extract, solid state fermentation was used; after which, L-cysteine and reduced Glutathione were added to the extracts, each treatment having four replicates including the control. The concentration of ammonia released was measured using a spectrophotometer at 600 nm. The control replicates exhibited higher activity compared to the two replicates; however, there was no significant difference in the concentrations of ammonia released by replicates treated with L-cysteine and reduced Glutathione. The mean value for control. L-cysteine-treated and reduced Glutathione- treated replicates is 7.948 x 10 mol/mg. 4.465 x 10 mol/mg and 3.17 x 10 mol/mg. respectively. It can be concluded that the presence of L-cysteine and reduced Glutathione will decrease the activity of E. coli l-asparaginase.