Molecular cloning and nucleotide sequence of the cDNA for human liver glutamate dehydrogenase precursor

Two cDNA clones (λGDHh1 and λGDHn61) for glutamate dehydrogenase (GDH) were isolated from a human liver cDNA library in λtll. The clone, λGDHh1, was isolated from the library using a synthetic 45mer oligodeoxy-ribonucleotide, the sequence of which was derived from the known amino acid sequence near the NH 2-terminus of human liver GDH. Subsequently, λGDHn61 was isolated from the same library using λGDHh1 as a probe. The inserts of both clones contained an overlapping cDNA sequence for human liver GDH, consisting of a 5′-untranslated region of 70 bp, an open reading frace of 1677 bp, a 3′-untranslated region of 1262 bp and a 15 base poly(A) tract. The predicted amino acid sequence revealed that the human liver GDH precursor consisted of a total of 558 amino acid residues including the NH 2-terminal presequence of 53 amino acids. The sequence deduced for the mature enzyme showed 94% homology to the previously reported amino acid sequence of human liver GDH.