Labelling of the human erythrocyte glucose transporter with 3H-labelled cytochalasin B occurs via protein photoactivation.
Irradiation of human erythrocyte membranes with 3H-labelled cytochalasin B results in specific photolabelling of the glucose transporter. The action spectrum of photolabelling has a maximum at approx. 280 nm, whereas the absorption spectrum of cytochalasin B is maximal at 210 nm. By irradiating with narrow-band-width light centered at 280 nm for 2 h, 8% of the transporters become covalently labelled and 47% of the remaining cytochalasin B-binding sites are obliterated. We conclude that photolabelling driven by narrow-bandwidth irradiation proceeds via photoactivation of an aromatic amino acid residue on the transporter molecule, and when compared to wide-bandwidth irradiation, permits more efficient incorporation of the label without causing additional photodamage to the remaining transporters.
D002352:Carrier Proteins / Q000378:metabolism* / Q000528:radiation effects; D003571:Cytochalasin B / Q000378:metabolism*; D004910:Erythrocyte Membrane / Q000378:metabolism*; D006801:Humans; D009004:Monosaccharide Transport Proteins; D010777:Photochemistry; D013057:Spectrum Analysis; D014466:Ultraviolet Rays
D002352:Carrier Proteins; D009004:Monosaccharide Transport Proteins; D003571:Cytochalasin B