Immobilized penicillin acylase performance during inactivation/reactivation cycles

Abstract

The enzyme L-asparaginase (L-asparagine amidohydrolase, EC 3.5.1.1) has been thoroughly researched by many researchers worldwide because of its immensely useful medical applications. It can catalyze the hydrolysis of L-asparagine to L-aspartic acid and ammonia that is effective for the cure of leukemia, especially for puerile acute lymphocytic leukemia [ALL] and lymphosarcomas. The tumor cells rely on an exogenous supply of Asn for their proliferation, and this enzyme causes selective death of asparagine-dependent tumor cells by depriving them of asparagine. L-Asparaginase is an intracellular enzyme, which is commonly obtained from microorganisms. The L-asparaginases of Erwinia and Escherichia coli have been reported for many years as effective drugs in the treatment of acute lymphoblastic leukemia. E. coli was shown to produce two distinct asparaginases which differ in several properties. The enzyme with the greater affinity, asparaginase II, appears to be located in the periplasmic space between the bacterial plasma membrane and the cell envelope. The present paper discusses the studies carried out for the optimal production of the enzyme from E. coli ATCC 11303. The nutritional requirements and culture conditions affecting biosynthesis of L-asparaginase II of E. coli ATCC 11303 were studied.

Effects of Two Trypsin Inhibitors on Trypsin in Activity and Structure

“…Covalent binding is a conventional one, and the support material ranged from agarose to SBA-15, from natural to synthetic ones [12]. Adsorption, entrapment，ionic binding， affinity binding，each method has its merits and demerits and seems to make a further step in enzyme immobilization [13][14][15]. But the concerned problem can't be solved effectively.…”