Topic
Amylase
About: Amylase is a research topic. Over the lifetime, 14164 publications have been published within this topic receiving 296069 citations.
Papers published on a yearly basis
Papers
More filters
••
TL;DR: The three-dimensional atomic structure of salivary amylase has been determined and it is found that the highly mobile glycine-rich loop 304-310 may act as a gateway for substrate binding and be involved in a 'trap-release' mechanism in the hydrolysis of substrates.
Abstract: Salivary α-amylase, a major component of human saliva, plays a role in the initial digestion of starch and may be involved in the colonization of bacteria involved in early dental plaque formation. The three-dimensional atomic structure of salivary amylase has been determined to understand the structure-function relationships of this enzyme. This structure was refined to an R value of 18.4% with 496 amino-acid residues, one calcium ion, one chloride ion and 170 water molecules. Salivary amylase folds into a multidomain structure consisting of three domains, A, B and C. Domain A has a (β/α)8− barrel structure, domain B has no definite topology and domain C has a Greek-key barrel structure. The Ca2+ ion is bound to Asnl00, Arg158, Asp167, His201 and three water molecules. The Cl− ion is bound to Arg195, Asn298 and Arg337 and one water molecule. The highly mobile glycine-rich loop 304–310 may act as a gateway for substrate binding and be involved in a `trap-release' mechanism in the hydrolysis of substrates. Strategic placement of calcium and chloride ions, as well as histidine and tryptophan residues may play a role in differentiating between the glycone and aglycone ends of the polysaccharide substrates. Salivary amylase also possesses a suitable site for binding to enamel surfaces and provides potential sites for the binding of bacterial adhesins.
253 citations
••
TL;DR: The system in vitro comprises the vectorial mechanism involved in the transfer of newly synthesized secretory protein across the endoplasmic reticulum membrane into the cisternal space.
251 citations
••
TL;DR: In this paper, a new strain of Bacillus sp. I-3, isolated from natural soil samples, showed a high raw starch digesting activity towards potato starch and reached 642 U/mL.
249 citations
••
TL;DR: The nature, amounts, and sequence of products formed from well-characterized substrates by the action of a crystalline α-type amylase from Bacillus subtilis were determined by qualitative and quantitative paper chromatography as discussed by the authors.
247 citations
••
TL;DR: Research in these areas, coupled with the development and use of isogeneic or near-isogeneic grain cultivars with biochemically defined endosperm characteristics, will enhance the ability to identify mechanisms to manipulate ruminal starch digestion.
Abstract: The effects of grain type and processing on ruminal starch digestion are well documented but poorly understood at the biochemical and molecular levels. Waxy grains have starches high in amylopectin and are more readily digested than nonwaxy grains. However, the composition of the endosperm cell matrix and the extent to which the starch granules are embedded within it also affect starch digestion rates. Continued work is needed to determine the influence of specific cell matrix proteins, protein-starch interactions and cell wall carbohydrates on starch availability. The microbial populations that metabolize starch are diverse, differing in their capacities to hydrolyze starch granules and soluble forms of starch. Surveys show that the amylases are under regulatory control in most of these organisms, but few studies have addressed the types of amylolytic enzymes produced, their regulation and the impact of other plant polymers on their synthesis. Research in these areas, coupled with the development and use of isogeneic or near-isogeneic grain cultivars with biochemically defined endosperm characteristics, will enhance our ability to identify mechanisms to manipulate ruminal starch digestion.
242 citations