Ms. Vincent et Ja. Near, PURIFICATION OF A [H-3] DIHYDROTETRABENAZINE-BINDING PROTEIN FROM BOVINE ADRENAL-MEDULLA, Molecular pharmacology, 40(6), 1991, pp. 889-894
A high affinity binding site for [H-3]dihydrotetrabenazine is thought
to be present on the monoamine transport protein from chromaffin granu
les. We describe a procedure for purification of this binding activity
from frozen bovine adrenal tissue, and we partially characterize the
purified preparation. Binding activity solubilized with sodium cholate
and soybean lecithin was fractionated on wheat germ lectin-Sepharose,
phenyl-Sepharose, Mono Q, and hydroxylapatite. Denaturing electrophor
esis of the purified binding activity, followed by silver staining, re
vealed a single broad band centered at an apparent molecular weight of
85,000. This preparation bound [H-3]dihydrotetrabenazine with an appa
rent dissociation constant of 2.7 nM and had a site density of 10 nmol
/mg. Treatment of the purified protein with neuraminidase reduced the
apparent molecular weight by 9000, indicating the presence of terminal
sialic acids on the oligosaccharide portion of this molecule.