Evidence for and Separation of Globular Hydrophobie and Non-Hydrophobic Forms of Acetylcholinesterase from Bovine Caudate Nucleus

Abstract

Almost complete removal of the deter-aggregates, which contained small amounts of gent from a purified 10.7 S complex consisting of bound residual Triton X-100 in the range of acetylcholinesterase and [ 3 H]Triton X-100 bound 0.4-1.6 mol Triton X-100 per mol acetylcholinto an affinity gel was achieved by extensive esterase. Besides these aggregates, a nearly deterwashing and subsequent elution of the enzyme. gent-free 10.5S form was observed, lacking the Applying this procedure of detergent removal, hydrophobic region responsible for detergent the majority of the enzyme could be stabilized binding and self-aggregation, by self-aggregation forming soluble 16S and 20 S Nachweis und Trennung von globulären hydrophoben und nicht hydrophoben Formen der Acetylcholinesterase aus dem Nucleus caudatus vom RindZusammenfassung: Der gereinigte, an ein Affini-20S-Aggregate, die noch geringe Reste von getätsgel gebundene 10.7S-Komplex bestehend aus bundenem Triton X-100 im Bereich von 0.4-1.6 Acetylcholinesterase und [ 3 H]Triton X-100 wur-mol Triton X-100 pro mol Acetylcholinesterase de durch mehrere Waschvorgänge und nachfolenthalten. Neben diesen Aggregaten wurde auch gende Elution fast vollständig vom Detergenz be-eine nahezu detergenzfreie 10.SS-Form nachgefreit. Wird das Detergenz auf diese Weise entfernt, wiesen, der die hydrophoben Bereiche, die sokann sich das Enzym durch Selbstaggregation wohl für die Detergenzbindung als auch die stabilisieren. Dabei entstehen lösliche 16S-und Selbstaggregation nötig sind, fehlen.

Molecular Forms of Acetylcholinesterase from Human Caudate Nucleus: Comparison of Salt‐Soluble and Detergent‐Soluble Tetrameric Enzyme Species

“…On extensive detergent removal, part of the enzyme self-micellarized to octamers and dodecamers of subunits. A fraction of the enzyme, however, remained as a tetramer that sedimented with an S value of 10.6 S. Landauer et al (1983) made a similar observation with the tetrameric DS-AChE from bovine brain, and these authors concluded that the enzyme fraction that did not aggregate lacked the hydrophobic regions responsible for detergent binding and self-aggregation. The aggregated human brain DS-AChE could be readily dissociated by readdition of micellar amounts of Triton X-100.…”

Bovine Nucleus Caudatus Acetylcholinesterase: Active Site Determination and Investigation of a Dimeric Form Obtained by Selective Proteolysis

“…Erythrocyte AChEs of various origins were reported to form ill-defined, polydisperse aggregates on detergent removal, with sedimentation coefficients ranging from 6 S to 20 S Lieflhder, 1975, 1979;Ott et al, 1975;Pesold et al, 1979). Under comparable conditions of detergent removal, the bovine NC AChE forms well-developed aggregates which contain small (16 S and 20 S forms) or even negligible (10.5 S form) amounts of residual detergent (Landauer et al, 1983). Whereas the polydisperse erythrocyte AChE aggregates are readily dissociated to the original erythrocyte AChE detergent complexes by reincubation with detergent, the bovine NC AChE aggregates are not dissociated by reincubation with nondenaturing detergents.…”

“…Sorensen et al (1982) have proved with human NC AChE that there exists a sizable hydrophobic segment which may be responsible for activity modulation on detergent binding and for ag-gregation and membrane anchoring as well. We have demonstrated with bovine N C AChE that hydrophobic protein regions are responsible for the characteristic aggregation behaviour of the 10.5 S AChE/detergent complex on detergent removal (Landauer et al. 1983).…”

“…We could not establish these results with bovine nucleus caudatus (NC) AChE (Ruess et al, unpublished results); the majority of this enzyme is solubilized only in the presence of detergents and is therefore classified as an integral membrane protein. This membranebound enzyme purified in the presence of Triton X-100 sediments as a 10.5 S AChEiTriton X-100 complex and was demonstrated to aggregate on detergent removal, forming definite 16 S and 20 S aggregates (Ruess and Lieflander, 1981;Landauer et al, 1983). The small amount of bovine NC AChE which is soluble in the cytoplasm sediments as a 10.5 S form with no sign of aggregation and not influenced by detergents (Ruess and Lieflander, 1981;Jonke, 1982).…”

Tetrameric Detergent‐Soluble Acetylcholinesterase from Human Caudate Nucleus: Subunit Composition and Number of Active Sites

“…In human caudate nucleus (Sdrensen et al, 1982), as in bovine (Landauer et al, 1983), rat (Rakonczay et al, 1981), pig (Reavill et al, 1978), and chicken brain tissue (Rotundo, 1984) most AChE activity can be assigned to a tetrameric, detergent-soluble form (DS-AChE). DS-AChE from human brain has been purified and characterized in our laboratory (Sdrensen et al, 1982;Gennari and Brodbeck, 1985).…”