B. amyloliquefaciens a-amylase

Later, MacGregor and MacGregor16 reported that barley malt a-amylase had an action pattern that was similar to that of B. amyloliquefaciens a-amylase, forming... 

Using molecular biology techniques, Conrad et al.61 produced hybrids of the a-amylases from B. amyloliquefaciens and B. licheniformis. Thirty-three hybrids were formed. They consisted of the entire a-amylase sequence with variable proportions from B. amyloliquefaciens a-amylase and B. licheniformis a-amylase. The hybrid enzymes fell into six groups that retained the extra-thermostability of the licheniformis enzyme. A specific hybrid sequence (residues 34-76) was correlated with the enzymes product specificity for forming and accumulating maltohexaose. Two of the hybrids were less thermostable than either of the parent types, while two others were enzymatically inactive. 

Kj values, however, were in the nanomolar range, with the Kj for the maltohexaosyl acarbose, 33 nM for A. oryzae a-amylase, 37 nM for B. amyloliquefaciens a-amylase, 14nM for human salivary a-amylase and 7.0nM for porcine pancreatic a-amylase. These inhibition constants represented relative inhibitory potency over acarbose of 8200-, 351 -, 90- and 114-times, respectively for the four a-amylases.220d... 

Disulfide interchange was also found to dominate mostly in another case the difference in half-lives r1/2 at 90°C and pH 6.5 of Bacillus a-amylases extended two orders of magnitude from Bacillus amyloliquefaciens through B. slearolhermophilus to B. licheniformis (Tomazic, 1988). For B. licheniformis a-amylase, deamidation of Asn/Gln residues was the main cause of inactivation. The cause of thermostability... 

Figure 7.21 Determination of the structure of Bacillus amyloliquefaciens a-amylase limit dextrin, using enzymes no reaction with (3-amylase (b) reaction with pullulanase to give maltose + maltotriose (c) reaction of glucoamylase to give two tetrasaccharides, both ofwhich are eventually converted into panose + glucose. Analysis of the reactions can be made by thin layer chromatography239.

Stephens, M.A., Ortlepp, S.A., Ollington, J.F. and McConnell, D.J., 1984, Nucleotide sequence of the 5 region of the Bacillus llcheniformis a-amylase gene comparison with the B. amyloliquefaciens gene, J. Bacterlol., 158 369. 

The immunological properties of a-amylases from transformable, transformant, and DNA-donor strains of Bacillus amyloliquefaciens B. natto, and B. subtilis have been compared. Most of the enzymes cross-reacted with each other s antibodies and contain at least twelve common peptide sequences. However, distinct structural differences were noted e.g. only two of the enzymes contain carbohydrate, which consists of neutral sugars and 2-amino-2-deoxy-D-glucose (9—11% total). 

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