PMID: 9178179May 1, 1997Paper

Investigation of physicochemical changes to L-asparaginase during freeze-thaw cycling

The Journal of Pharmacy and Pharmacology
F JameelD Kalonia

Abstract

L-Asparaginase derived from Erwinia chrysanthemi which is being investigated as an alternative to E. coli for the treatment of lymphoblastic leukaemia has been found in our laboratory to lose activity upon exposure to consecutive freeze-thaw cycles. An investigation was undertaken using several techniques to characterize fully the physicochemical changes L-Asparaginase is undergoing during freeze-thaw cycling leading to the loss of its activity. A total protein assay suggested that the loss of some enzyme activity was a result of protein precipitation. Circular dichroism (CD) studies showed a decrease of alpha-helical structure with a concomitant increase in beta sheet and random coil content, suggesting alterations in the secondary structure leading to unfolding, the first step of denaturation processes. The elution profiles obtained from size-exclusion chromatography (SEC) studies indicated the formation of several species during the process of freezing and thawing. Sodium dodecylsulphate-polyacrylamide gel electrophoresis (SDS-PAGE) studies showed bands corresponding to 1-3 kDa and 32 kDa, suggesting that some of the species are fragments and shortened monomers resulting from cleavage of monomers. The molecular weight distri...Continue Reading

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Citations

Nov 26, 2002·Cryobiology·J C BischofJ H Crowe
May 13, 2010·Journal of Biomechanical Engineering·Ka Yaw TeoBumsoo Han
Dec 24, 2015·Critical Reviews in Biotechnology·André Moreni LopesAdalberto Pessoa
Oct 3, 2006·Critical Reviews in Oncology/hematology·Umesh K NartaWamik Azmi
Mar 31, 2015·International Journal of Pharmaceutics·Madeleine WittingSarah Hedtrich
Jul 31, 2009·Journal of Biomechanical Engineering·Ka Yaw Teo, Bumsoo Han

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