Tissue-specific isoforms of the gamma-subunit of the bovine FoF1-ATP synthase were identified for the first time. The two isoforms, heart and liver type, were generated by alternative splicing, the liver-type RNA transcript containing a 37-nucleotide sequence as a cassette exon. Protein sequencing of the C-terminal fragments of the two isoforms of the F1 gamma-subunit indicated that the liver-type isoform had an additional aspartate residue at the C terminus, not present in the heart type one.