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A D‐Glucose‐Sensitive Cytochalasin B Binding Component of Cerebral Microvessels
Author(s) -
Baldwin S. A.,
Cairns M. T.,
Gardiner R. M.,
Ruggier R.
Publication year - 1985
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.1471-4159.1985.tb04039.x
Subject(s) - cytochalasin b , glucose transporter , cytochalasin , blood–brain barrier , biochemistry , photoaffinity labeling , chemistry , cytochalasin d , biophysics , biology , cytoskeleton , binding site , central nervous system , endocrinology , in vitro , cell , insulin
The technique of photoaffinity labelling with [4‐ 3 H]cytochalasin B was applied to osmotically lysed cerebral microvessels isolated from sheep brain. Cytochalasin B was photo‐incorporated into a membrane protein of average apparent M r 53,000. Incorporation of cytochalasin B was inhibited by D‐glucose, but not by L‐glucose, which strongly suggests that the labelled protein is, or is a component of, the glucose transporter of the blood–brain barrier. Investigation of noncovalent [4‐ 3 H]cytochalasin B binding to cerebral microvessels by equilibrium dialysis indicated the presence of a single set of high‐affinity binding sites with an association constant of 9.8 ± 1.7 (SE) μ M −1 . This noncovalent binding was inhibited by D‐glucose, with a K i of 23 m M. These results provide preliminary identification of the glucose transporter of the ovine blood–brain barrier, and reveal both structural and functional similarities to the glucose transport protein of the human erythrocyte.