| Autor: |
Hansen G; Institute for Biochemistry, Charité University Clinic, Humboldt University of Berlin, Germany., Heese O, Höhne WE, Hofemeister B |
| Jazyk: |
angličtina |
| Zdroj: |
International journal of peptide and protein research [Int J Pept Protein Res] 1994 Sep; Vol. 44 (3), pp. 245-52. |
| DOI: |
10.1111/j.1399-3011.1994.tb00167.x |
| Abstrakt: |
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. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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