title: Sequence conservation of the catalytic regions of amylolytic enzymes in maize branching enzyme-I.
abstract: We have identified cDNA clones encoding branching enzyme-I (BE-I) from a maize kernel cDNA library. The combined nucleotide sequence of the cDNAs indicates that maize BE-I is initially synthesized as a precursor protein with a putative 64-residue transit peptide at the amino terminus, and that the mature enzyme contains 759 amino acid residues with a calculated molecular mass of 86,236 Da. The four regions, which constitute the catalytic site of amylolytic enzymes, are conserved in the sequences of BE-I and bacterial branching enzymes. This result demonstrates that branching enzyme belongs to a family of the amylolytic enzymes. The BE-I gene is highly expressed in the early stages of kernel development, and the level of the message concentration decreases slowly as kernel maturation proceeds.
authors.affiliation: Institute of Applied Biochemistry, University of Tsukuba, Ibaraki, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Baba
authors.forename: K
authors.initials: K
authors.lastname: Kimura
authors.forename: K
authors.initials: K
authors.lastname: Mizuno
authors.forename: H
authors.initials: H
authors.lastname: Etoh
authors.forename: Y
authors.initials: Y
authors.lastname: Ishida
authors.forename: O
authors.initials: O
authors.lastname: Shida
authors.forename: Y
authors.initials: Y
authors.lastname: Arai
mesh_terms: D015061:1,4-alpha-Glucan Branching Enzyme / Q000235:genetics*; D000595:Amino Acid Sequence; D001419:Bacteria / Q000201:enzymology / Q000235:genetics; D001483:Base Sequence; D001665:Binding Sites; D003001:Cloning, Molecular; D004247:DNA / Q000235:genetics; D004792:Enzyme Precursors / Q000096:biosynthesis / Q000235:genetics; D015723:Gene Library; D006801:Humans; D008969:Molecular Sequence Data; D005810:Multigene Family; D012313:RNA / Q000235:genetics / Q000302:isolation & purification; D015183:Restriction Mapping; D012689:Sequence Homology, Nucleic Acid; D003313:Zea mays / Q000201:enzymology / Q000235:genetics* / Q000254:growth & development; D000516:alpha-Amylases / Q000235:genetics
chemical_list: D004792:Enzyme Precursors; D012313:RNA; D004247:DNA; D015061:1,4-alpha-Glucan Branching Enzyme; D000516:alpha-Amylases