alpha-Amylases from Thermoactinomyces vulgaris: characteristics, primary structure and structure prediction.
Two amylolytic active protein fractions (named alpha-amylase 1 and alpha-amylase 2) were isolated from the bacterium Thermoactinomyces vulgaris strain 94-2A. alpha-Amylase 1 had a molecular mass of 51.6 kDa, whereas alpha-amylase 2 consists of two fragments which have molecular masses of 17.0 and 34.6 kDa, respectively. These two fragments are products from a proteolytic cleavage of alpha-amylase 1 at amino acid position 303 (tryptophan) by a serine protease (thermitase) which is also produced by T. vulgaris. The purified alpha-amylase 1 and 2 follow the Michaelis-Menten kinetics in the presence of starch as substrate with Km values of 1.37 +/- 0.07 and 1.29 +/- 0.18 mg/mL, respectively. In effect they differ in their stability characteristics. The amino acid sequence of alpha-amylase from T. vulgaris derived from DNA sequence (1) was compared with those of other alpha-amylases. It reveals high homologies to alpha-amylases from other microorganisms (e.g. B. polymyxa, A. oryzae, S. occidentalis and S. fibuligera). A three-dimensional structure model for alpha-amylase 1 on the basis of the 3 A X-ray structure of Taka-amylase was constructed.
Hansen
G
G
Institute for Biochemistry, Charité University Clinic, Humboldt University of Berlin, Germany.
Heese
O
O
Höhne
W E
WE
Hofemeister
B
B
D000595:Amino Acid Sequence; D002851:Chromatography, High Pressure Liquid; D017124:Conserved Sequence; D018360:Crystallography, X-Ray; D003488:Cyanogen Bromide; D008848:Micromonosporaceae / Q000201:enzymology*; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry / Q000302:isolation & purification; D017433:Protein Structure, Secondary; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000302:isolation & purification; D017386:Sequence Homology, Amino Acid; D012697:Serine Endopeptidases; D014357:Trypsin; D000516:alpha-Amylases / Q000096:biosynthesis / Q000737:chemistry* / Q000302:isolation & purification
D010446:Peptide Fragments; D011994:Recombinant Proteins; D000516:alpha-Amylases; D012697:Serine Endopeptidases; C022728:thermitase; D014357:Trypsin; D003488:Cyanogen Bromide