Reactions of alpha amylases with starch granules in aqueous suspension giving products in solution and in a minimum amount of water giving products inside the granule

Yook, Cheol; Robyt, John F.

doi:10.1016/s0008-6215(02)00107-6

Cited by 50 publications

(29 citation statements)

References 15 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…It is less than half of the degree of polymerization for the unhydrolyzed maltodextrin. This level of polymerization is in good agreement with the previous results on the mechanism of hydrolysis of oligosaccharides by α-amylase from Bacillus amyloliqu efaciens [42][43][44]. They demonstrated that the α-amylase cannot hydrolyze short oligomers, such as G 5 , G 4 , G 3 or G 2 and the hydrolysis of oligomers with 6 units, G 6 , proceeds very slowly to G 5 + G 1 [43], while oligomers with 8 units, G 8 are mainly degraded to G 6 + G 2 and G 5 + G 3 , and oligomers with 7 units, G 7 produce…”

Section: Frequencies 5 and 8 Mhzsupporting

confidence: 92%

“…Figure 5 shows the real-time ultrasonic profile of hydrolysis of maltodextrin, a mixture of linear saccharides, G n , composed mainly of 7 and 8 glucose units with average degree of polymerization 7.55 catalyzed by α-amylase (Bacillus amyloliqu efaciens). α-amylases are enzymes that hydrolyze the α-(1-4) linkages of such polymers as starch, amylose, amylopectin, glycogen, and dextrins [42][43][44]. The hydrolysis can be represented as:…”

Section: Examples Of Ultrasonic Reaction Progress Curvesmentioning

confidence: 99%

See 1 more Smart Citation

Ultrasonic Monitoring of Biocatalysis in Solutions and Complex Dispersions

Buckin

Altas

2017

Catalysts

View full text Add to dashboard Cite

Abstract:The rapidly growing field of chemical catalysis is dependent on analytical methods for non-destructive real-time monitoring of chemical reactions in complex systems such as emulsions, suspensions and gels, where most analytical techniques are limited in their applicability, especially if the media is opaque, or if the reactants/products do not possess optical activity. High-resolution ultrasonic spectroscopy is one of the novel technologies based on measurements of parameters of ultrasonic waves propagating through analyzed samples, which can be utilized for real-time non-invasive monitoring of chemical reactions. It does not require optical transparency, optical markers and is applicable for monitoring of reactions in continuous media and in micro/nano bioreactors (e.g., nanodroplets of microemulsions). The technology enables measurements of concentrations of substrates and products over the whole course of reaction, analysis of time profiles of the degree of polymerization and molar mass of polymers and oligomers, evolutions of reaction rates, evaluation of kinetic mechanisms, measurements of kinetic and equilibrium constants and reaction Gibbs energy. It also provides tools for assessments of various aspects of performance of catalysts/enzymes including inhibition effects, reversible and irreversible thermal deactivation. In addition, ultrasonic scattering effects in dispersions allow real-time monitoring of structural changes in the medium accompanying chemical reactions.

show abstract

Section: Frequencies 5 and 8 Mhzsupporting

confidence: 92%

Section: Examples Of Ultrasonic Reaction Progress Curvesmentioning

confidence: 99%

Ultrasonic Monitoring of Biocatalysis in Solutions and Complex Dispersions

Buckin

Altas

2017

Catalysts

View full text Add to dashboard Cite

show abstract

“…Thus, in the genetic absence of Tas1r3, pharmacological inhibition of disaccharidases eliminated all responses to the disaccharide sugars sucrose and maltose. Discussion Starch, a dietary staple for humans and rodents alike, is initially digested into oligo-and disaccharides by salivary and pancreatic amylases (23)(24)(25). The intestinal brush border enzymes MGAM, SIS, TREH, and LCT then convert disaccharides maltose, sucrose, trehalose, and lactose into readily absorbable monosaccharides (16,17).…”

Section: Resultsmentioning

confidence: 99%

Taste cell-expressed α-glucosidase enzymes contribute to gustatory responses to disaccharides

Sukumaran

Yee

Iwata

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

The primary sweet sensor in mammalian taste cells for sugars and noncaloric sweeteners is the heteromeric combination of type 1 taste receptors 2 and 3 (T1R2+T1R3, encoded by Tas1r2 and Tas1r3 genes). However, in the absence of T1R2+T1R3 (e.g., in Tas1r3 KO mice), animals still respond to sugars, arguing for the presence of T1R-independent detection mechanism(s). Our previous findings that several glucose transporters (GLUTs), sodium glucose cotransporter 1 (SGLT1), and the ATP-gated K + (K ATP ) metabolic sensor are preferentially expressed in the same taste cells with T1R3 provides a potential explanation for the T1R-independent detection of sugars: sweet-responsive taste cells that respond to sugars and sweeteners may contain a T1R-dependent (T1R2+T1R3) sweet-sensing pathway for detecting sugars and noncaloric sweeteners, as well as a T1R-independent (GLUTs, SGLT1, K ATP ) pathway for detecting monosaccharides. However, the T1R-independent pathway would not explain responses to disaccharide and oligomeric sugars, such as sucrose, maltose, and maltotriose, which are not substrates for GLUTs or SGLT1. Using RT-PCR, quantitative PCR, in situ hybridization, and immunohistochemistry, we found that taste cells express multiple α-glycosidases (e.g., amylase and neutral α glucosidase C) and so-called intestinal "brush border" disaccharide-hydrolyzing enzymes (e.g., maltase-glucoamylase and sucrase-isomaltase). Treating the tongue with inhibitors of disaccharidases specifically decreased gustatory nerve responses to disaccharides, but not to monosaccharides or noncaloric sweeteners, indicating that lingual disaccharidases are functional. These taste cell-expressed enzymes may locally break down dietary disaccharides and starch hydrolysis products into monosaccharides that could serve as substrates for the T1R-independent sugar sensing pathways.gustation | sensory transduction | disaccharides | sucrase-isomaltase | maltase-glucoamylase

show abstract

“…PPA is an endo-type amylase and it catalyzes the hydrolysis of internal a-(1,4) glycosidic bonds in amylose and amylopectin through multiple attack toward the nonreducing end (Robyt & French, 1970). The products of hydrolysis of porcine pancreatic a-amylase are mainly maltose, maltotriose, and maltotetraose (Yook & Robyt, 2002). PPA has two isomers PPA isozyme-I (PPA-I) and PPA-II, which have the same molecular weight but differ slightly in amino acid composition and isoelectric point (Pasero et al, 1986).…”

Section: Stilbenes (Fig 37)mentioning

confidence: 99%