title: Two synpatic vesicle proteins of 25 kDa: a comparison of the molecular properties and tissue distribution of svp25 and o-rab3.
abstract: Two synaptic vesicle proteins of the electric ray Torpedo--svp25 and o-rab3--are compared with respect to their biochemical properties and tissue distribution. On SDS-PAGE both proteins migrate to the same position of about 25 kDa. As revealed by application of monospecific antibodies and subcellular fractionation both proteins comigrate and cofractionate with the synaptic vesicle compartment. o-Rab3 and svp25 can be separated by lectin chromatography; svp25 is highly glycosylated and binds to concanavalin A sepharose. Upon deglycosylation using glycopeptidase F and O-glycosidase its apparent molecular mass is reduced to about 14 kDa. Partial amino acid sequences obtained by direct microsequencing of purified and deglycosylated svp25 revealed that svp25 is a novel protein that has not yet been characterized in molecular terms. Whereas svp25 was detected in all brain areas investigated, the expression of o-rab3 was found to be restricted to specific regions. An immunoblot analysis demonstrates an exclusive association of both proteins with neural tissues. Our results suggest that cholinergic synaptic vesicles from electric ray electric organ contain at least two membrane-associated proteins of an apparent molecular mass of 25 kDa, the membrane associated o-rab3 and the membrane integral protein svp25. The two proteins can be separated by lectin chromatography for assessment of their biochemical properties.
authors.affiliation: Zoologisches Institut der Universität, Biozentrum, Frankfurt/M., Germany.
authors.forename: A
authors.initials: A
authors.lastname: Hausinger
authors.forename: W
authors.initials: W
authors.lastname: Volknandt
authors.forename: S
authors.initials: S
authors.lastname: Kretzschmar
authors.forename: R
authors.initials: R
authors.lastname: Kellner
authors.forename: H
authors.initials: H
authors.lastname: Zimmermann
mesh_terms: D000818:Animals; D015153:Blotting, Western; D003208:Concanavalin A; D004557:Electric Organ / Q000294:innervation / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D006023:Glycoproteins / Q000096:biosynthesis; D006868:Hydrolysis; D008562:Membrane Glycoproteins / Q000737:chemistry / Q000378:metabolism*; D008970:Molecular Weight; D009419:Nerve Tissue Proteins / Q000737:chemistry / Q000378:metabolism*; D010275:Parasympathetic Nervous System / Q000378:metabolism; D017421:Sequence Analysis; D013572:Synaptic Vesicles / Q000378:metabolism*; D014018:Tissue Distribution; D014101:Torpedo / Q000378:metabolism*
chemical_list: D006023:Glycoproteins; D008562:Membrane Glycoproteins; D009419:Nerve Tissue Proteins; C103463:synaptic vesicle protein svp25, Torpedo; D003208:Concanavalin A