Ben-Hur E, Dubbelman T M, Van Steveninck J
Sylvius Laboratory, Department of Medical Biochemistry, Leiden, The Netherlands.
Photochem Photobiol. 1991 Nov;54(5):703-7. doi: 10.1111/j.1751-1097.1991.tb02078.x.
Fluoride inhibits chloroaluminum phthalocyanine tetrasulfonate (AlPcS)-induced photohemolysis when added to dye loaded cells prior to light exposure. The mechanism by which F- exerts this effect was studied by measuring the binding of phthalocyanine (Pc) to various proteins in the absence and presence of F-. Parallel measurements were made of the photodynamic action under these conditions. Fluoride reduced the binding to proteins of AlPcS and CoPcS. The binding of CuPcS, ZnPcS and H2PcS was not affected. When bound to bovine serum albumin and exposed to light, H2Pc, ZnPc and AlPcCl were bleached at a biphasic rate. Only the photobleaching of AlPcCl was affected by F-. The effect of F- was to inhibit the initial rapid phase without affecting the slower phase. In the presence of D2O only the second phase of photobleaching was enhanced, in the absence or presence of F-. No effect of F- was observed on tryptophan photooxidation or glyceraldehyde-3-phosphate dehydrogenase photoinactivation by AlPcS. Crosslinking of spectrin monomers photosensitized by AlPcS was inhibited by F- in parallel with the reduced binding of dye to the protein. It is concluded that F- exerts its effect by complexing with metal ligands of Pc. As a result, the dye may be released from the protein or the binding mode may be changed in such a way that effective photochemistry is prevented. Primary photophysical processes of Pc most probably are not affected by F-.
在光照前将氟化物添加到负载染料的细胞中时，它可抑制四磺化氯铝酞菁（AlPcS）诱导的光溶血。通过测量在有无氟化物的情况下酞菁（Pc）与各种蛋白质的结合，研究了氟离子发挥这种作用的机制。在这些条件下对光动力作用进行了平行测量。氟化物减少了AlPcS和CoPcS与蛋白质的结合。CuPcS、ZnPcS和H2PcS的结合不受影响。当与牛血清白蛋白结合并暴露于光下时，H2Pc、ZnPc和AlPcCl以双相速率被漂白。只有AlPcCl的光漂白受到氟化物的影响。氟化物的作用是抑制初始快速相而不影响较慢的相。在有无氟化物的情况下，仅在重水存在时光漂白的第二相增强。未观察到氟化物对AlPcS诱导的色氨酸光氧化或甘油醛-3-磷酸脱氢酶光失活有影响。AlPcS光敏化的血影蛋白单体的交联被氟化物抑制，这与染料与蛋白质结合减少平行。结论是氟化物通过与Pc的金属配体络合发挥其作用。结果，染料可能从蛋白质中释放出来，或者结合模式可能改变，从而阻止有效的光化学作用。Pc的初级光物理过程很可能不受氟化物影响。
