title: Characterization of active barley alpha-amylase 1 expressed and secreted by Saccharomyces cerevisiae.
abstract: Recombinant barley alpha-amylase 1 isozyme was constitutively secreted by Saccharomyces cerevisiae. The enzyme was purified to homogeneity by ultrafiltration and affinity chromatography. The protein had a correct N-terminal sequence of His-Gln-Val-Leu-Phe-Gln-Gly-Phe-Asn-Trp, indicating that the signal peptide was efficiently processed. The purified alpha-amylase had an enzyme activity of 1.9 mmol maltose/mg protein/min, equivalent to that observed for the native seed enzyme. The kcat/Km was 2.7 x 10(2) mM(-1) x s(-1), consistent with those of alpha-amylases from plants and other sources.
authors.affiliation: Western Regional Research Center, USDA-ARS, Albany, California 94710, USA. dwdw@pw.usda.gov
authors.forename: D W
authors.initials: DW
authors.lastname: Wong
authors.forename: S B
authors.initials: SB
authors.lastname: Batt
authors.forename: G H
authors.initials: GH
authors.lastname: Robertson
mesh_terms: D001467:Hordeum / Q000201:enzymology*; D007525:Isoelectric Focusing; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism*; D000516:alpha-Amylases / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*
chemical_list: D010940:Plant Proteins; D011994:Recombinant Proteins; D000516:alpha-Amylases