Amylase

About: Amylase is a research topic. Over the lifetime, 14164 publications have been published within this topic receiving 296069 citations.

Microbial and physiological characterization of weakly amylolytic but fast-growing lactic acid bacteria: a functional role in supporting microbial diversity in pozol, a Mexican fermented maize beverage.

Abstract: Pozol is an acid beverage obtained from the natural fermentation of nixtamal (heat- and alkali-treated maize) dough. The concentration of mono- and disaccharides from maize is reduced during nixtamalization, so that starch is the main carbohydrate available for lactic acid fermentation. In order to provide some basis to understand the role of amylolytic lactic acid bacteria (ALAB) in this fermented food, their diversity and physiological characteristics were determined. Forty amylolytic strains were characterized by phenotypic and molecular taxonomic methods. Four different biotypes were distinguished via ribotyping; Streptococcus bovis strains were found to be predominant. Streptococcus macedonicus, Lactococcus lactis, and Enterococcus sulfureus strains were also identified. S. bovis strain 25124 showed extremely low amylase yield relative to biomass (139 U g [cell dry weight]−1) and specific rate of amylase production (130.7 U g [cell dry weight]−1 h−1). In contrast, it showed a high specific growth rate (0.94 h−1) and an efficient energy conversion yield to bacterial cell biomass (0.31 g of biomass g of substrate−1). These would confer on the strain a competitive advantage and are the possible reasons for its dominance. Transient accumulation of maltooligosaccharides during fermentation could presumably serve as energy sources for nonamylolytic species in pozol fermentation. This would explain the observed diversity and the dominance of nonamylolytic lactic acid bacteria at the end of fermentation. These results are the first step to understanding the importance of ALAB during pozol fermentation.

Inhibitory effect of clonal oregano extracts against porcine pancreatic amylase in vitro.

Abstract: Oregano (Origanum vulgare) is a rich source of natural phenolic antioxidants and has potential to be a source of nutritional ingredients for functional foods. Herbs such as oregano have long been used in food preservation and in traditional medicine in the treatment of common ailments and have potential for positive modulation of oxidation-linked diseases such as diabetes. One of the potentially important components of anti-diabetic activity by oregano extract is mild amylase inhibition by phenolic antioxidants to help contribute towards management of hyperglycemia. Previously, we reported the ability of rosmarinic acid, one of the principal phenolic components of oregano, to inhibit porcine pancreatic amylase (PPA) activity. Here, we investigated the effect of 50% ethanol extracts of eleven phenolic antioxidant-rich oregano clonal lines on the activity of PPA in vitro. To this end, we analyzed extract total soluble phenolic content by the Folin-Ciocalteu reagent method, rosmarinic acid (RA), protochatechuic acid (PA), quercetin, and p-coumaric acid (pCA) contents by HPLC, antioxidant activity as 1,1-diphenyl-2-picryl-hydrazyl (DPPH) radical scavenging, and PPA-inhibitory activity by incubation of the enzyme with clonal oregano extracts and characterization of the activity of the phenolic-bound enzyme. Clonal oregano extracts inhibited the activity of PPA in vitro by 9-57%. Amylase inhibition by oregano extract was associated with extract total phenolic content and RA, quercetin, PA, and pCA content, as well as extract antioxidant activity and protein content. Our finding that clonal oregano extracts can inhibit PPA supports a potential new functionality for oregano as an anti-hyperglycemic agent. This provides an opportunity for a food-based strategy for modulation of starch breakdown to glucose, which could contribute to the management of hyperglycemia and diabetes complications in the long term.

Amylase variants in Drosophila melanogaster: linkage studies and characterization of enzyme extracts.

Abstract: The amylases of D. melanogaster were characterized by several parameters. Starch-iodine and 3,5-dinitrosalicylic acid reduction methods were employed to determine activity. Conditions were defined under which activity, in crude aqueous extracts could be restricted to α-amylase(s) of fly origin. Biochemical properties of the α-amylases from eleven homozygous Amy strains were found to be very similar in temperature stability, pH optimum, substrate specificity and the effects of various activators and inhibitors. All were activated by chloride ions and showed a pH optimum of about 7.4. Relative efficiencies on several substrates were tested: soluble starch, amylopectin, β-limit dextrins, glycogen and amylose. EDTA completely inhibited all extracts, presumably by the removal of calcium required for activation. The specific α-amylase inhibitor from wheat grain also completely inhibited activity, as did reduced glutathione. PCMB had no discernible effects on activity. Eight of the 11 strains tested are known to produce different electrophoretic banding patterns for amylases. The total maximum activity of each strain may also be used to characterize it and, accordingly, three strains with amylases of the same electrophoretic mobility were distinguished by differences in their specific activities. Sexual dimorphism in amylase activity was defined, as well as activity in heterozygotes between strains. Aside from the distinctions between strains already noted, four strains differed in their relative susceptibility to heat and to α-amylase inhibitor. Linkage experiments indicated that the Amy region lies at 77.3 on the genetic map of the second chromosome and to the right, but near, section 52F on the salivary chromosome map.