MECHANISTIC STUDIES ON ASPARAGINASE FROM ESCHERICHIA-COLI .10. THE ISOTOPE EFFECT IN C-13 NUCLEAR-MAGNETIC-RESONANCE SPECTROSCOPY
MECHANISTIC STUDIES ON ASPARAGINASE FROM ESCHERICHIA-COLI .10. THE ISOTOPE EFFECT IN C-13 NUCLEAR-MAGNETIC-RESONANCE SPECTROSCOPY
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DOI：
10.1016/0003-9861(86)90101-3
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发表时间：
1986-01-01
影响因子：
3.9
通讯作者：
VANETTEN, RL
中科院分区：
文献类型：
--
作者：
ROHM, KH;VANETTEN, RL
The mechanism of the enzyme asparaginase (l-asparagine amidohydrolase, EC 3.5.1.1) fromEscherichia coliwas examined using13C NMR spectroscopy. The pH-dependent oxygen exchange reactions between water and aspartic acid were followed by use of the18O isotope-induced shift of the resonance positions of directly bonded13C nuclei. Bothl-1- andl-1,4-[13C]aspartic acid were used in experiments with previously18O-labeled aspartic acid, or in experiments involving the use of18O-labeled solvent water. Asparaginase catalyzes a relatively efficient exchange between the oxygens of water and those on one carboxyl group of aspartic acid. Exchange at C-4 occurs rapidly but, within experimental error, no exchange at C-1 could be detected. These and related experiments involving the position of18O incorporation during hydrolysis of aspartic acid β-methyl ester are all consistent with possible acyl-enzyme mechanisms involving C-4, but do not support a free aspartic acid anhydride mechanism.
