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Existence of two membrane‐bound acetylcholinesterases in the honey bee head
Author(s) -
Badiou Alexandra,
Brunet JeanLuc,
Belzunces Luc P.
Publication year - 2007
Publication title -
archives of insect biochemistry and physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.576
H-Index - 66
eISSN - 1520-6327
pISSN - 0739-4462
DOI - 10.1002/arch.20204
Subject(s) - acetylcholinesterase , aché , elution , chromatography , membrane , chemistry , phosphatidylinositol , phospholipase c , ionic strength , biochemistry , enzyme , organic chemistry , kinase , aqueous solution
Abstract Two acetylcholinesterase (EC 3.1.1.7) membrane forms AChE m1 and AChE m2 , have been characterised in the honey bee head. They can be differentiated by their ionic properties: AChE m1 is eluted at 220 mM NaCl whereas AChE m2 is eluted at 350 mM NaCl in anion exchange chromatography. They also present different thermal stabilities. Previous processing such as sedimentation, phase separation, and extraction procedures do not affect the presence of the two forms. Unlike AChE m1 , AChE m2 presents reversible chromatographic elution properties, with a shift between 350 to 220 mM NaCl, depending on detergent conditions. Purification by affinity chromatography does not abolish the shift of the AChE m2 elution. The similar chromatographic behaviour of soluble AChE strongly suggests that the occurrence of the two membrane forms is not due to the membrane anchor. The two forms have similar sensitivities to eserine and BW284C51. They exhibit similar electrophoretic mobilities and present molecular masses of 66 kDa in SDS‐PAGE and a sensitivity to phosphatidylinositol‐specific phospholipase C in non‐denaturing conditions, thus revealing the presence of a glycosyl‐phosphatidylinositol anchor. We assume that bee AChE occurs in two distinct conformational states whose AChE m2 apparent state is reversibly modulated by the Triton X‐100 detergent into AChE m1 . Arch. Insect Biochem. Physiol. 66:122–134, 2007. © 2007 Wiley‐Liss, Inc.