Purification, cDNA cloning and heterologous expression of the human mitochondrial NADP(+)-dependent malic enzyme

• Published in: Biochemical journal 1994-12, Vol.304 ( Pt 3) (3), p.687-692
• Main Authors: Loeber, G, Maurer-Fogy, I, Schwendenwein, R
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Animals; Base Sequence; Blotting, Northern; Cattle; Cloning, Molecular; DNA Primers; DNA, Complementary - genetics; DNA, Complementary - isolation & purification; Escherichia coli - enzymology; Escherichia coli - genetics; Female; Hippocampus - enzymology; Humans; Isoenzymes - genetics; Kinetics; Malate Dehydrogenase - genetics; Malate Dehydrogenase - isolation & purification; Malate Dehydrogenase - metabolism; Male; Mitochondria, Heart - enzymology; Molecular Sequence Data; Open Reading Frames; Polymerase Chain Reaction; RNA, Messenger - analysis; Sequence Homology, Amino Acid; Tissue Distribution; Transcription, Genetic
• ISSN: 0264-6021; 1470-8728
• DOI: 10.1042/bj3040687

Mitochondrial NADP(+)-dependent malic enzyme (ME; EC 1.1.1.39) has been purified to homogeneity and characterized kinetically from bovine heart. Partial amino acid sequence information allowed amplification of a specific bovine cDNA, which was used to isolate a full-length human cDNA of this isoform of ME. The cDNA is 1930 bp long and codes for a protein of 604 amino acids. Comparison of the amino acid sequence of this isoform with published sequences of other human ME isoforms shows stretches of homology interrupted by larger regions with significant differences. The human protein has been expressed in Escherichia coli, and the recombinant human protein has the same kinetic properties as the corresponding protein purified from bovine heart. Northern blot analysis showed a strong tissue-specific transcription with a predominantly high expression-rate in organs with a low division-rate.