A-amylases, use

An example of a direct spectrophotometrical assay is the use of synthetic peptide -nitroanilide substrates to determine protease activity. The /)-nitroani1ine group Hberated from the substrates by the protease can be determined spectrophotometricaHy at 410 nm. An example of an indirect (coupled) spectrophotometric assay is the determination of a-amylase using -nitrophenyLmaltoheptaoside. Initially, the substrate is cleaved by the a-amylase and subsequentiy one of the reaction products, -nitrophenyLmaltotrioside, is cleaved by a-glucosidase, hberating -nitrophenyl, a chromophore... 

Bacterial a-amylases used in laundry detergents are fully compatible with detergent proteases, ie, the two enzymes work together in the wash process. During storage in both powder and Hquid detergents, the amylases are very stable in the presence of proteases. 

Very recently, Lazarova and Tonova [53] reported an integrated process for extraction and stripping of a-amylase using RMs in a stirred cell with separated compartments for each process. A comparison between the classical process and the integrated process indicated a 1.27-fold enhancement in the enzyme purification by the latter. This integrated process was operated with 100 ml volume in... 

Increased serum activity of a-amylase indicates several internal diseases. The enzyme catalyzes the stepwise hydrolysis of starch and oligosaccharides to maltose. Since studies with a-amylase use rather heterogeneous substrates, comparison of the given activities is often impossible. 

Topographical Comparisons of Family 13 a-Amylases using Molecular Modelling Techniques... 

Figure 3.99 shows Wang s data on the hydrolysis of starch by a-amylase using the same MWCO membrane. Here the difference in carbohydrate concentrations between retentate and permeate is much larger because the products of a-amylase hydrolysis are predominantly maltose and larger dextrins. Eventually the dextrins are hydrolyzed to glucose, but at a slower rate. Thus, the carbohydrate concentration in the reactor increases with time. These results suggest that the selection of membrane MWCO can control the products of the reaction. 

Figure 4.9 Hydrolysis of maltoheptaose by a-amylase using sonication technique.

Tateno T, Fukuda H, Kondo A. (2007b). Direct production of L-lysine from raw com starch by Corynebacterium glutamicum secreting Streptococcus bovis a-amylase using cspB promoter and signal sequence. Appl Microbiol Biotechnol, 77, 533-541. 

Various methods have been proposed for the determination of RS, e. g., RS equals total starch minus digestible starch. The results are only comparable if the incubation conditions and the a-amylases used correspond. 

Okamoto, S., Chin, X, Nagata, K., Xakahashi, X. et al (2015) Production of itaconic acid in Escherichia coli expressing recombinant a-amylase using starch as substrate. /. Bioscl Bioeng,... 

Coconut oil cake is a waste by-product obtained after the oil extraction fium dried coconut. The major compounds fium the coconut oil cake are short chain saturated fatty acids, which were proposed to be used as a carbon substrate somce in solid-state fermentation (SSF) for enzymes biosynthesis. This approach in which the coconut oil cake represents a cheap way for the bioproducts synthesis is a new one and was adopted in the last years. The first report on enzymes synthesis using coconut oil cake was published by Ramachandran and coworkers, in 2004. The researchers optimized the production of a-amylase using a fungal culture of Aspergillus oryzae strain in SSF cultivation system on a medium based on raw coconut oil cake and it was obtained an a-amylase activity of 1372 U/g dw, in 24 h. Eight... 

Maheswari, N. U. Soundariya, S. (2012). Coconut oil cake - A novel substrate of solid state fermentation for the produetion of a-amylase using Streptomyces spp. JOCPR, 4(7), 3383-3386. 

---