Open AccessEffects of Amphiphiles on Structure and Activity of Human Erythrocyte Membrane Acetylcholinesterase
Author(s) -
WIEDMER Therese,
FRANCESCO Cristina,
BRODBECK Urs
Publication year - 1979
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1979.tb06262.x
Subject(s) - chemistry , acetylcholinesterase , lysophosphatidylcholine , amphiphile , sodium dodecyl sulfate , enzyme , membrane , critical micelle concentration , biochemistry , vesicle , chromatography , sodium cholate , micelle , biophysics , organic chemistry , phospholipid , phosphatidylcholine , biology , aqueous solution , copolymer , polymer
Detergents above their critical micellar concentration dissociate the aggregated forms of pure acetylcholinesterase from human erythrocyte membranes to a 6.5‐S form, the protomer. This form is active only in presence of amphiphiles.1 Uncharged (Triton X‐100, Tweens, β‐ d ‐octylglycoside), anionic (sodium dodecyl sulfate) and zwitterionic (lysophosphatidylcholine) detergents or bile salts (sodium cholate, deoxycholate) stabilize the 6.5‐S enzyme at concentrations well below their critical micellar concentration. 2 Total erythrocyte lipids fully sustain catalytic activity of the 6.5‐S form. 3 Protein‐protein interactions stabilize the activity of the 6.5‐S form of acetylcholinesterase. Above a critical acetylcholinesterase concentration (2.5 μg/ml) enzyme activity no longer depends on the presence of an amphiphile as reaggregation to multiple molecular forms occurs.It is concluded that human erythrocyte membrane acetylcholinesterase is fully active only if the enzyme can undergo hydrophobic interactions with amphiphiles such as detergents, lipids or proteins.