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The mitochondrial oxoglutarate carrier protein contains a disulfide bridge between intramembranous cysteines 221 and 224
Author(s) -
Bisaccia F.,
Capobianco L.,
Mazzeo M.,
Palmieri F.
Publication year - 1996
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(96)00784-3
Subject(s) - chemistry , cysteine , maleimide , cleavage (geology) , reagent , biochemistry , reducing agent , stereochemistry , organic chemistry , enzyme , biology , paleontology , fracture (geology)
The oxoglutarate carrier (OGC) purified from bovine heart mitochondria was treated, both in its active and in its SDS‐denatured state, with the fluorescent N ‐(1‐pyrenyl)maleimide and other SH reagents before and after reduction with dithioerythritol or β‐mercaptoethanol. The number of SH groups per OGC polypeptide chain was found to be about 1 for the oxidized carrier and 3 for the reduced carrier. The bovine oxoglutarate carrier contains three cysteines: Cys‐184, Cys‐221 and Cys‐224. Sequencing of BrCN cleavage products of oxoglutarate carrier showed that N ‐(1‐pyrenyl)maleimide binds to only Cys‐184 of the oxidized protein and also to Cys‐221 and Cys‐224 after reduction of the protein. These results show the presence of a disulfide bridge between the latter two cysteines of the purified carrier. The oxidized and the reduced forms of the oxoglutarate carrier exhibited different V max but virtually the same K m values for oxoglutarate.