ALPHA-AMYLASES FROM THERMOACTINOMYCES-VULGARIS - CHARACTERISTICS, PRIMARY STRUCTURE AND STRUCTURE PREDICTION

作者：HANSEN G^*; HEESE O; HOHNE WE; HOFEMEISTER B

来源：International Journal of Peptide and Protein Research, 1994, 44(3): 245-252.

• ALPHA-AMYLASE
• KINETICS
• NONGLUCOGENIC
• SEQUENCE
• STRUCTURE PREDICTION
• THERMOACTINOMYCES VULGARIS
• THERMOSTABILITY

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 a-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 K-m 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 Angstrom X-ray structure of Taka-amylase was constructed.

• 出版日期1994-9