M icrochip CE‐ LIF method for the hydrolysis of L‐glutamine by using L‐asparaginase enzyme reactor based on gold nanoparticle

l ‐Asparaginase ( l ‐ A snase) can suppress the growth of malignant cells by rapid depletion of two essential amino acids, l ‐glutamine ( l ‐ G ln) and l ‐asparagine ( l ‐ A sn). To study the cytotoxic effect and the secondary complications of l ‐ A snase in the treatment of acute lymphoblastic leukemia, the development of a novel enzyme reactor of l ‐ A snase for the hydrolysis of l ‐ G ln, employing the enzyme‐gold nanoparticle conjugates in capillary, was reported in this work. First, a microchip CE (MCE)‐ LIF was established for the separation of l ‐amino acids ( l ‐ G ln and l ‐glutamic acid) and studying the hydrolysis of l ‐ G ln by using l ‐ A snase enzyme reactor. Then, using l ‐ G ln as target analyte, the enzyme kinetics of l ‐ A snase in free solution, enzyme‐gold nanoparticle conjugates ( E ‐ GNP ), and the enzyme‐gold nanoparticle conjugates immobilized in capillary ( E ‐ GNP ‐ C ) were investigated in detail with the proposed MCE ‐ LIF method. Moreover, for optimizing the enzymatic reaction efficiency, three important parameters, including the length of capillary, the enzyme concentration reacted with gold nanoparticle and the amount of l ‐ A snase immobilized on the gold nanoparticle, have been studied. Owing to the high specific activity, the E ‐ GNP ‐ C enzyme reactor exhibited the best performance for the hydrolysis of l ‐ G ln.