Structural and functional degradation of Ca2+:Mg2+-ATPase rich sarcoplasmic reticulum vesicles photosensitized by erythrosin B.
Erythrosin B (Red Dye No. 3) and Rose Bengal photosensitize the destruction of the Ca2+:Mg2+-ATPase pump protein in sarcoplasmic reticulum (SR) vesicles with respective quantum efficiencies of (1.53 +/- 0.19) X 10(-3) and (1.25 +/- 0.18) X 10(-3). Damage to vesicle function was assayed by measurements of increases in passive Ca2+ permeability. Rates of passive Ca2+ movement into the SR lumen were increased by dye photosensitization in proportion to radiation absorbed. Active Ca2+ transport into SR vesicles was blocked independent of radiation absorbed by Erythrosin B and Rose Bengal at free concentrations of 0.69 microM and 1.16 microM, respectively. The photochemical lability of the Ca2+ pump protein and alterations in passive and active Ca2+ transport may be dependent on the concentration of the dye in the membrane. The photosensitization results may have implications with respect to the suitability of Erythrosin B usage in vivo, since the brightness of our irradiation source is comparable to that of sunlight at 480 nm.
D000818:Animals; D001692:Biological Transport; D017301:Ca(2+) Mg(2+)-ATPase; D002118:Calcium / Q000378:metabolism; D000252:Calcium-Transporting ATPases / Q000378:metabolism* / Q000528:radiation effects; D004396:Coloring Agents / Q000494:pharmacology*; D004591:Electrophoresis, Polyacrylamide Gel; D004923:Erythrosine / Q000494:pharmacology*; D005452:Fluoresceins / Q000494:pharmacology*; D008027:Light; D011817:Rabbits; D012395:Rose Bengal / Q000494:pharmacology; D012519:Sarcoplasmic Reticulum / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism* / Q000528:radiation effects
D004396:Coloring Agents; D005452:Fluoresceins; D012395:Rose Bengal; D017301:Ca(2+) Mg(2+)-ATPase; D000252:Calcium-Transporting ATPases; D004923:Erythrosine; D002118:Calcium