Isolation and characterization of an allelic cDNA for human muscle fructose-1,6-bisphosphatase.
By applying a newly developed method, cDNAs for the human muscle isoform of fructose-1,6-bisphosphatase were isolated from phage- and plasmid-derived libraries. From these cDNAs and an EST clone, a composite sequence (1302 bp) was deduced that contains an open reading frame encoding a polypeptide of 339 amino acids with an estimated molecular weight of 36 755. After overexpression in E. coli, recombinant human muscle fructose 2,6-bisphosphatase was found to be active in cel-free extracts and could be strongly inhibited by AMP and fructose 2,6-bisphosphate. Sequence comparisons revealed that (1) all amino acids thought to be in contact with substrate molecules, regulatory molecules or metal ions in mammalian liver fructose-1,6-bisphosphatases are, with one exception, conserved in the human muscle enzyme and (2) the human muscle isoform is more homologous to the mouse intestine fructose-1,6-bisphosphatase than to the mammalian liver isoform. This is the first report of the cloning and expression of a muscle fructose-1,6-bisphosphatase isoenzyme.
Institute of Biochemistry, University of Leipzig, School of Medicine, Leipzig, Germany.
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Tillmann
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Eschrich
D000483:Alleles; D000595:Amino Acid Sequence; D001483:Base Sequence; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000737:chemistry* / Q000302:isolation & purification*; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics; D006597:Fructose-Bisphosphatase / Q000096:biosynthesis / Q000235:genetics* / Q000302:isolation & purification; D015870:Gene Expression; D005822:Genetic Vectors / Q000235:genetics; D006801:Humans; D007527:Isoenzymes / Q000096:biosynthesis / Q000235:genetics / Q000302:isolation & purification; D008969:Molecular Sequence Data; D018482:Muscle, Skeletal / Q000201:enzymology*; D016366:Open Reading Frames; D016133:Polymerase Chain Reaction; D011994:Recombinant Proteins / Q000096:biosynthesis; D012045:Regulatory Sequences, Nucleic Acid; D017386:Sequence Homology, Amino Acid
D018076:DNA, Complementary; D007527:Isoenzymes; D011994:Recombinant Proteins; D006597:Fructose-Bisphosphatase