Reversible Dissociation of L-Asparaginase of Escherichia coli B
1972; Elsevier BV; Volume: 61; Issue: 5 Linguagem: Inglês
10.1002/jps.2600610526
ISSN1520-6017
AutoresA. Aszalós, Joel Kirschbaum, Oleh T. Ratych, Niklas Kraemer, Octavian Kocy, David J. Frost, J.P. Casey,
Tópico(s)Biochemical and Molecular Research
ResumoA large conformational change can be induced in l-asparaginase of Escherichia coli B, purified by heat treatment, by the addition of 0.0026 M sodium dodecyl sulfate to a 3.8–7.4 × 10−6M enzyme solution. Optical rotatory dispersion and circular dichroism measurements indicated that conformational change occurs simultaneously with dissociation of the tetrameric enzymes to the size of a dimer (20,w0 = 4.05), as shown by ultracentrifugal measurements, and with a decrease of activity in vitro. This change can be reversed by the addition of sodium sulfate, sodium citrate, or dipotassium hydrogen phosphale. Simultaneously, the enzyme regains its original molecular weight of 130,000 daltons (s20,w0 = 8.75) and its full activity in vitro.
Referência(s)