Alpha-amylase 519

Figure 7.9 Topological structures of a-amylase A. Two-dimensional representation of the secondary and domain structures of porcine pancreatic a-amylase. Alpha helices are represented as circles and (3-strands in the up-direction as squares, and in the down direction as double squares. The (a/(3)g—TIM barrel comprises domain A. Hydrogen bonds between (3-strands are shown by dashed lines. The a-helices and (3-strands are identified in the various domains by A, B and C. (Reprinted by permission ofthe authors M. Qian et al.120) Two-dimensional representation ofthe secondary and domain structures of barley malt a-amylase (AMY2-2). Alpha helices are represented as cylinders and (3-strands as arrows. The (a/(3)g—TIM barrel comprises domain A, with eight (3-strands and an equivalent of eight a-helices. The active-site is composed ofthe loops that connect the C-termini ofthe (3-strands to the N-termini ofthe peripheral a-helices. (Adapted from A. Kadziola et al.121)...

A widely-used method to adjust the viscosity of a starch dispersion to a target level uses amylases. Alpha-amylase catalyzes hydrolysis of starch molecules by breaking a-D-(l,4)-glucosidic bonds at random, generating depolymerization products, a-(l,4 ... 

Fig. 1. Enzymatic liquefaction processes (9). Alpha-S is the a-amylase from bacillus subtilis alpha-L/ST are a-amylases from B. licheniformis oi B.

Alpha-amylases are characterized by attacking the starch polymer in an endo fashion, randomly cleaving internal 1,4-bonds to yield shorter, water-soluble dextrins. They are the preferred type of amylase for laundry detergents, and are included in both powder and Hquid formulations in many countries. 

Carba-oligosaccharidic Alpha Amylase Inhibitors and Related Compounds. . 81... 

Carba-glycosylamines [2,3,4-trihydroxy-5-(hydroxymethyl)-1 -cyclohex-ylamine] and related compounds are well known to exist as components of the antibiotic validamycin complex and carba-oligosaccharidic alpha amylase inhibitors. ... 

Several mono-carba-oligosaccharidic alpha amylase inhibitors, such as acarbose and its homologs, amylostatins, trestatins, oligostatins, adipo-sins, and so on, have been isolated from cultures of micro-organisms, and considerable interest in the biochemistry and chemistry of this class of inhibitors has been stimulated. The characteristic core-structure for inhibitory action is composed of a trihydroxy(hydroxymethyl)cyclohexene moiety and a 4-amino-4,6-dideoxy-D-glucopyranose moiety, bonded by way of an imino linkage at the allylic position. A similar structural unit has been found in the antibiotic validamycins. 

ISHIMOTO M, YAMADA T, KAGA A (1999) Insecticidal activity of an alpha-amylase inhibitor-like protein resembling a putative precursor of alpha-amylase inhibitor in the common bean, Phaseolus vulgaris L. Biochim Biophys Acta. 1432 104-12. 

MIRKOV T E, EVANS S V, WAHLSTROM J, GOMEZ L, YOUNG N M, CHRISPEELS M J (1995) Location of the active site of the bean alpha-amylase inhibitor and involvement of a Trp, Arg, Tyr triad. Glycobiology. 5 45-50. 

Expression of the insecticidal bean alpha-amylase inhibitor transgene has minimal detrimental effect on the nutritional value of peas fed to rats at 30% of the diet. JNutr. 129 1597-603. 

Palva, I. (1982) Molecular cloning of alpha-amylase gene from Bacillus amyloliquefaciens and its expression in B. subtilis. Gene, 19 (1), 81-87. 

Landry, T.D., Chew, L., Davis, J.W. et al. (2003) Safety evaluation of an alpha-amylase enzyme preparation derived from the archaeal order Thermococcales as expressed in Pseudomonas fluorescens biovar I. Regulatory Toxicology and Pharmacology, 37 (1), 149-168. 

Payre, N., Cottaz, S. and Driguez, H. (1995). Chemoenzymatic synthesis of a modified pentasaccharide as a specific substrate for a sensitive assay of alpha-amylase by fluorescence quenching. Angew. Chem. Int. Ed. Engl. 34, 1239-1241. 

A product manufactured in Japan as Alo mixture (Anomalously Linked Oligosaccharides) contains mainly a range of IMOS (glucose, isomaltose, and panose as principal constituents). It is produced from starch as substrate by the action of alpha-amylase, beta-amylase, and a transglucosidase. It is claimed to have favorable properties for application in the food industry.143... 

E. A. MacGregor, H. M. Jespersen, and B. Svensson, A circularly permuted alpha-amylase-type alpha/beta-barrel structure in glucan-synthesizing glucosyl-transferases, FEBS Lett., 378 (1996) 263-266. 

L. K. Skov, O. Mirza, A. Henriksen, G. P. De Montalk, M. Remaud-Simeon, P. Sarcabal, R. M. Willemot, P. Monsan, and M. Gajhede, Amylosucrase, a glucan-synthesizing enzyme from the alpha-amylase family, J. Biol. Chem., 276 (2001) 25273-25278. 

Caldwell, Mary L., and Adams, Mildred, Action of Certain Alpha Amylases, V, 229-268... 

Signs of nickel deficiency in the laboratory white rat (Rattus sp.) include retarded growth, anemia, a reduction in hematocrit and hemoglobin values, decreased enzyme activities (malate dehydrogenase, glucose-6-phosphate dehydrogenase, alpha amylase), a reduction in liver total lipids... 

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