J. Saezvalero et al., AMPHIPHILIC AND HYDROPHILIC FORMS OF ACETYLCHOLINESTERASE AND BUTYRYLCHOLINESTERASE IN HUMAN BRAIN, Journal of neuroscience research, 35(6), 1993, pp. 678-689
Human brain acetylcholinesterase (AChE) and butyrylcholinesterase (BuC
hE) were sequentially extracted, first with a Tris-saline buffer (S1)
and then c with 1 % (w/v) Triton X-100 (S2). About 20 and 30 % of the
AChE and BuChE activities were recovered in S1 and most of the remaini
ng enzymes in S2. Main molecular forms of about 10.5 S and 12.0 S, G4
forms of AChE and BuChE, and smaller amounts of 4.5 S and 5.5 S forms,
G1 species of AChE and BuChE, were measured in S1. Application of Tri
ton X-114 phase partitioning and affinity chromatography on phenyl-aga
rose to S1 revealed that 25% of the AChE and none of the BuChE molecul
es displayed amphiphilic properties. Analysis of the enzyme activity r
etained by the phenyl-agarose showed that G1 AChE constituted the bulk
of the amphiphilic molecules released without detergent. Main G4 form
s of AChE and BuChE were found in the S2 extract. Eighty and 45% of th
e AChE and BuChE activities in S2 were measured in the detergent-rich
phase by Triton X-114 phase partitioning. Thus, most of the AChE and a
bout half of the BuChE molecules in S2 displayed amphiphilic propertie
s. The main peak of BuChE, a 12.0 S form in gradients made with Triton
X-100, splits into two peaks of 9.5 S and 12.5 S in Brij 96-containin
g gradients. This suggests that hydrophilic G4 BuChE forms are predomi
nant in S1 and that hydrophilic and amphiphilic isoforms coexist in S2
. (C) 1993 Wiley-Liss, Inc.