ISSN:
1573-4943
Keywords:
butyrylcholinesterase
;
acid
;
salt
;
Hofmeister series
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
Notes:
Abstract Human serum butyrylcholinesterase (EC 3.1.1.8) loses 100% of its activity toward butyrylthiocholine in 60 min atpH 3.0. This deactivation is retarded by 1.37 M ammonium sulfate to a loss of 40% after 60 min atpH 3.0. Reneutralization experiments suggest that the mechanism for this acid inactivation does not exclusively involve hydrolysis of peptide bonds or protonation of the enzyme's active site. Studies with different anions and cations demonstrate that the order of their effectiveness as protective agent against acid inactivation closely follows the Hofmeister series. No relationship was found between catalytic activation or inhibition by salt and protection from acid inactivation. Ultraviolet difference studies at 288 nm with enzyme brought topH 2.7 frompH 8.0 in the presence and absence of 1.37 M ammonium sulfate demonstrated no change in UV absorbance with ammonium sulfate present and approximately a 0.15 ODU rise in absorbance in the absence of ammonium sulfate. These results suggest that acidicpH conditions result in deactivating stereochemical changes in the active site of butyrylcholinesterase and that certain anions and cations, according to the Hofmeister series, are able to protect the enzyme from acid inactivation by stabilizing the active conformation of its active site.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01024880
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