Existence of uncoupling protein-2 antigen in isolated mitochondria from various tissues

Antibodies against Escherichia coli-expressed uncoupling protein-2 (UCP2) a nd uncoupling protein-3 (UCP3) were raised by operating the blotted protein s into the spleen of minipigs, The antisera reacted more intensively with t he recombinant UCP2 and UCP3 than with uncoupling protein-1 (UCP1) isolated from brown adipose tissue. Moreover, anti-UCP2 and cross-reacting anti-UCP 3 antibodies identified the presence of the UCP2/3 antigen in isolated mito chondria from rat heart, rat kidney, rat brain, rabbit epididymal white adi pose tissue, hamster brown adipose tissue, and rabbit skeletal muscle. It h as been concluded that UCP2 is expressed in these tissues (UCP3 in skeletal muscle); however their existence in mitochondria had not previously been d emonstrated. (C) 1999 Federation of European Biochemical Societies.