J. Saezvalero et Cj. Vidal, BIOCHEMICAL-PROPERTIES OF ACETYLCHOLINESTERASE AND BUTYRYLCHOLINESTERASE IN HUMAN MENINGIOMA, Biochimica et biophysica acta. Molecular basis of disease, 1317(3), 1996, pp. 210-218
The structural properties of acetyl-(AChE) and butyrylcholinesterase (
BuChE) in meningioma and the possible relationship with brain and plas
ma were investigated. Meningioma ChEs were extracted with saline and s
aline-Triton X-100 buffers. The tumor ChE forms were identified by sed
imentation analysis, and their amphiphilic/hydrophilic behaviour was a
ssessed by Triton X-114 phase-partitioning and hydrophobic chromatogra
phy. Meningioma contained amphiphilic globular AChE dimers (G(2)(A)) a
nd monomers (G(1)(A)), and hydrophilic BuChE tetramers (G(4)(H)). The
conversion of G(2)(A) into G(1)(A) AChE by reduction confirmed their s
tructures. In contrast to the meningioma species, brain G(1)(A) AChE f
orms remained amphiphilic after incubation with alkaline hydroxylamine
and phosphatidylinositol-specific A phospholipase C (PIPLC). Meningio
ma G(1)(A) and PIPLC-converted G(1)(H) and brain G(1)(A) AChE showed s
imilar rate constants for thermal inactivation, and this suggested tha
t the thermal stability of AChE subunits was unaffected by the presenc
e or not of phosphatidylinositol residues. AChE in meningioma and brai
n did not differ in the interaction with the lectins Con A, LCA, WGA a
nd RCA. BuChE in meningioma and brain bound to a similar extent to Con
A, LCA and WGA-Agarose, whereas one half of BuChE in the tumor, all i
n plasma and little in brain was fixed by RCA. Therefore, meningioma p
ossesses RCA(+)- and RCA(-)-BuChE, the former predominating in brain a
nd the latter in plasma. It remains to be clarified whether the tumor
RCA(+)-BuChE is intrinsic or derived from plasma.