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Calpain Inhibitor I Prevents Rapid Postmortem Degradation of Benzodiazepine Binding Proteins: Fluorographic and Immunological Evidence
Author(s) -
Reichelt Ralf,
Möhler Hanns,
Hebebrand Johannes
Publication year - 1990
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1990.tb04960.x
Subject(s) - proteolysis , calpain , protease , gel electrophoresis , chemistry , endogeny , protease inhibitor (pharmacology) , flunitrazepam , biochemistry , polyacrylamide gel electrophoresis , microbiology and biotechnology , enzyme inhibitor , receptor , enzyme , benzodiazepine , biology , immunology , human immunodeficiency virus (hiv) , antiretroviral therapy , viral load
Endogenous proteolysis of the major central benzodiazepine (BZ) binding protein of 53K occurs rapidly postmortem and leads to a fragment of 47K. To determine indirectly the protease responsible for this proteolysis, membranes of porcine cortex were prepared from homogenates. which were either frozen immediately or left at room temperature for 12 h in the presence or absence of various representative protease inhibitors. Membranes were subsequently photolabeled with [ 3 H]flunitrazepam, and subjected to sodium dodecyl sulfate‐polyacrylamide gel electrophoresis and fluorography or immunoblotted using an α‐subunit‐specific monoclonal antibody bd‐24. Both fluorographs and imraunoblots revealed that calpain inhibitor I, Ep‐459 (E‐64 analogue), and EDTA (±1 m M ) prevent endogenous proteolysis. In future studies one of these inhibitors should be added to receptor preparations. The results indicate that calpain is the responsible protease.