Protoporphyrin-induced photodynamic effects on band 3 protein of human erythrocyte membranes |
| |
Authors: | TMAR Dubbelman AFPM De Goeij K Christianse J Van Steveninck |
| |
Institution: | Sylvius Laboratories, Department of Medical Biochemistry, Wassenaarseweg 72, 2333 AL Leiden The Netherlands |
| |
Abstract: | In previous studies it has been shown that protoporphyrin-induced photodynamic effects on red blood cells are caused by photooxidation of amino acid residues in membrane proteins and by the subsequent covalent cross-linking of these proteins. Band 3, the anion transport protein of the red blood cell membrane, has a relatively low sensitivity to photodynamic cross-linking. This cannot be attributed to sterical factors inherent in the specific localization of band 3 in the membrane structure. Solubilized band 3, for instance, showed a similar low sensitivity to cross-linking. By extracellular chymotrypsin cleavage of band 3 into fragments of 60 000 and 35 000 daltons it could be shown that both fragments were about equally sensitive to photodynamic cross-linking. The 17 000 dalton transmembrane segment, on the other hand, was completely insensitive. Inhibition of band 3-mediated sulfate transport proceeded much faster than band 3 interpeptide cross-linking, presumably indicating that the inhibition of transport is caused by photooxidation of essential amino acid residues or intrapeptide cross-linking. A close parallel was observed between photodynamic inhibition of anion transport and decreased binding of 4,4′-diisothiocyanodihydrostilbene-2,2′-disulfonate (H2DIDS), suggesting that a photooxidation in the immediate vicinity of the H2DIDS binding site may be responsible for transport inhibition. |
| |
Keywords: | Photodynamic effect Photo-oxidation Cross-linking Protoporphyrin Band 3 protein (Human erythrocyte) 4 4′-diisothiocyanodihydrostilbene-2 2′-disulfonate SDS sodium dodecyl sulfate |
本文献已被 ScienceDirect 等数据库收录! |
|