Abstract

The cDNA sequence encoding the murine liver E1β subunit of the branched-chain α-ketoacid dehydrogenase complex (BCKAD) was determined. In the region encoding the mature E1β subunit protein, both the nucleotide composition and predicted amino acid sequence are highly conserved between murine, rat, human, and bovine species. In contrast, they are less well conserved in the 5′ sequence encoding the amino terminal preprotein sequence and 3′ untranslated region. The pattern of tissue-specific expression of three BCKAD subunit RNAs was determined to be similar in both rat and murine tissues except for that observed in murine liver, where a higher than expected level of E1β subunit RNA was observed. Variation in the levels of this subunit might play a major role in the regulation of the overall ability of the murine liver to modulate BCKAD content in response to changing physiologic needs.

Keywords: Branched-chain α-ketoacid dehydrogenase; RNA; E1β subunit; Murine tissue-specific expression; cDNA; Ketoacid dehydrogenase; (Mouse liver)