( sup 125 I)Iodoazidococaine, a photoaffinity label for the haloperidol-sensitive sigma receptor

Journal Article · Sat Feb 15 00:00:00 EST 1992 · Proceedings of the National Academy of Sciences of the United States of America; (United States)

DOI:https://doi.org/10.1073/pnas.89.4.1393· OSTI ID:5687076

Kahoun, J R; Ruoho, A E ^[1]

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1. Univ. of Wisconsin, Madison (United States)

A carrier-free radioiodinated cocaine photoaffinity label, (-)-3-({sup 125}I)iodo-4-azidococaine (({sup 125}I)IACoc), has been synthesized and used as a probe for cocaine-binding proteins. Photoaffinity labeling with 0.5 nM ({sup 125}I)IACoc resulted in selective derivatization of a 26-kDa polypeptide with the pharmacology of a sigma receptor in membranes derived from whole rat brain, rat liver, and human placenta. ({sup 125}I)IACoc labeling of the 26-kDa polypeptide was also inhibited by 10 {mu}M imipramine, amitriptyline, fluoxetine, benztropine, and tetrabenazine. The size of the ({sup 125}I)I-ACoc-labeled proteins is consistent with the size of proteins photolabeled in guinea pig brain and liver membranes by using the sigma photolabel azido-({sup 3}H)DTG. Kinetic analysis of ({sup 125}I)IACoc binding to rat liver microsomes revealed two sites with K{sub d} values of 19 and 126 pM, respectively. The presence or absence of proteolytic inhibitors during membrane preparation did not alter the size of the photolabeled sigma receptor, indicating that the 26-kDa polypeptide was not derived from a larger protein. In summary, ({sup 125}I)IACoc is a potent and highly specific photoaffinity label for the haloperidol-sensitive sigma receptor and will be useful for its biochemical and molecular characterization.

• OSTI ID: 5687076
• Journal Information: Proceedings of the National Academy of Sciences of the United States of America; (United States), Vol. 89:4; ISSN 0027-8424
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRY
PROTEINS
RADIORECEPTOR ASSAY
RADIOPHARMACEUTICALS
BIOSYNTHESIS
AZIDO COMPOUNDS
BRAIN
COCAINE
IODINE 125
LIVER
PLACENTA
RECEPTORS
ALKALOIDS
ANESTHETICS
ANTIDEPRESSANTS
BETA DECAY RADIOISOTOPES
BODY
CENTRAL NERVOUS SYSTEM
CENTRAL NERVOUS SYSTEM AGENTS
CENTRAL NERVOUS SYSTEM DEPRESSANTS
DAYS LIVING RADIOISOTOPES
DIGESTIVE SYSTEM
DRUGS
ELECTRON CAPTURE RADIOISOTOPES
FETAL MEMBRANES
GLANDS
INTERMEDIATE MASS NUCLEI
INTERNAL CONVERSION RADIOISOTOPES
IODINE ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
LABELLED COMPOUNDS
MEMBRANE PROTEINS
MEMBRANES
NERVOUS SYSTEM
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANS
PSYCHOTROPIC DRUGS
RADIOISOTOPES
SYNTHESIS
TRACER TECHNIQUES
550201* - Biochemistry- Tracer Techniques
400702 - Radiochemistry & Nuclear Chemistry- Properties of Radioactive Materials