The binding of α‐amylase to starch plays a decisive role in the initiation of storage starch degradation in turions of <i>Spirodela polyrhiza</i>

Reimann, Rezarta; Ziegler, Paul; Appenroth, Klaus‐J.

doi:10.1111/j.1399-3054.2006.00816.x

Cited by 12 publications

(25 citation statements)

References 37 publications

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“…The total phosphate content of deproteinated starch granules was determined colorimetrically by the phosphomolybdate method of Worsfold, Clinch & Casey (1987) as described by Reimann et al. (2007).…”

Section: Methodsmentioning

confidence: 99%

“…Deproteinated, lyophilized starch granules were incubated with α ‐amylase partially purified from the turions irradiated for 24 h with continuous R, and were then washed as described by Reimann et al. (2007).…”

Section: Methodsmentioning

confidence: 99%

“…In previous papers, we have demonstrated that important features of the light‐induced breakdown of the turion starch are phosphorylation of the starch and a concomitant association of the hydrolytic starch‐degrading enzyme α ‐amylase with the starch (Reimann et al. 2004; Reimann, Ziegler & Appenroth 2007). In the present paper, we have investigated whether nitrate is required for light‐induced starch degradation in S. polyrhiza , and, if so, at which point in the induction process it exerts its effect.…”

Section: Introductionmentioning

confidence: 99%

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Light‐induced degradation of storage starch in turions of Spirodela polyrhiza depends on nitrate

Appenroth

Ziegler

2008

Plant Cell & Environment

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Light induces both the germination of turions of the duckweed Spirodela polyrhiza and the degradation of the reserve starch stored in the turions. The germination photoresponse requires nitrate, and we show here that nitrate is also needed for the light-induced degradation of the turion starch. Ammonium cannot substitute for nitrate in this regard, and nitrate thus acts specifically as signal to promote starch degradation in the turions. Irradiation with continuous red light leads to starch degradation via autophosphorylation of starch-associated glucan, water dikinase (GWD), phosphorylation of the turion starch and enhanced binding of a-amylase to starch granules. The present study shows that all of these processes require the presence of nitrate, and that nitrate exerts its effect on starch degradation at a point between the absorption of light by phytochrome and the auto-phosphorylation of the GWD. Nitrate acts to coordinate carbon and nitrogen metabolism in germinating turions: starch will only be broken down when sufficient nitrogen is present to ensure appropriate utilization of the released carbohydrate. These data constitute the first report of control over the initiation of reserve starch degradation by nitrate.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Light‐induced degradation of storage starch in turions of Spirodela polyrhiza depends on nitrate

Appenroth

Ziegler

2008

Plant Cell & Environment

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“…Lemnaceae have also been used to solve questions in basic research, e.g. in photosynthesis (Booij-James et al 2009), phytohormone biosynthesis (Rapparini et al 1999) or starch degradation (Reimann et al 2007). Li et al (2004) and Yamamoto et al (2001) reported genetic transformation of some duckweed species, although stable transformation still awaits optimization.…”

Section: Introductionmentioning

confidence: 99%

Genetic structure of the genus Lemna L. (Lemnaceae) as revealed by amplified fragment length polymorphism

Bog¹,

Baumbach²,

Schween

et al. 2010

Planta

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Duckweeds (Lemnaceae) are extremely reduced in morphology, which made their taxonomy a challenge for a long time. The amplified fragment length polymorphism (AFLP) marker technique was applied to solve this problem. 84 clones of the genus Lemna were investigated representing all 13 accepted Lemna species. By neighbour-joining (NJ) analysis, 10 out of these 13 species were clearly recognized: L. minor, L. obscura, L. turionifera, L. japonica, L. disperma, L. aequinoctialis, L. perpusilla, L. trisulca, L. tenera, and L. minuta. However, L. valdiviana and L. yungensis could be distinguished neither by NJ cluster analysis nor by structure analysis. Moreover, the 16 analysed clones of L. gibba were assembled into four genetically differentiated groups. Only one of these groups, which includes the standard clones 7107 (G1) and 7741 (G3), represents obviously the "true" L. gibba. At least four of the clones investigated, so far considered as L. gibba (clones 8655a, 9481, 9436b, and Tra05-L), represent evidently close relatives to L. turionifera but do not form turions under any of the conditions tested. Another group of clones (6745, 6751, and 7922) corresponds to putative hybrids and may be identical with L. parodiana, a species not accepted until now because of the difficulties of delineation on morphology alone. In conclusion, AFLP analysis offers a solid base for the identification of Lemna clones, which is particularly important in view of Lemnaceae application in biomonitoring.

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“…α-Amylase (EC 3.2.1.1, α-(1, 4)-glucan-4-glucanohydrolase), which catalyses the hydrolysis of α-(1, 4) glycosidic linkages in starches, is one of the main enzymes in the digestive tract (Bompard-Gilles, Rousseau, Rougé, & Payan, 1996;Warren, Zhang, Waltzer, Gidley, & Dhital, 2015). Starch digestion by α-amylase involves two steps: binding of the enzyme with starch and a subsequent hydrolysis process; therefore, the adsorption and binding of α-amylase to starch is necessary before the catalytic step can proceed (Patel, Day, Butterworth, & Ellis, 2014) and affects the digestion of starch to some extent (Reimann, Ziegler, & Appenroth, 2007). For the case of starch granules, as their size (0.5-50 µm, radius) is much greater than that of α-amylase (ca 3nm, hydrodynamic radius) (Dhital, Shrestha, & Gidley, 2010;Larson, Day, & McPherson, 2010), the adsorption of the enzyme onto starch granules depends on the number and accessibility of available binding sites on the granules (Warren, Royall, Gaisford, Butterworth, & Ellis, 2011).…”

Section: Introductionmentioning

confidence: 99%

Studying the interactions between tea polyphenols and α-amylase

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Dixon, Cornish-Bowden and Lineweaver-Burk plot analyses were applied to study the detailed kinetics of inhibition of porcine pancreatic α-amylase (PPA) by tea polyphenols.Fluorescence quenching (FQ), differential scanning calorimetry (DSC) and isothermal titration calorimetry (ITC) were combined with the kinetics of inhibition to elucidate the mechanism of binding interactions of tea polyphenols and PPA. Then, the reciprocal of competitive inhibition constant (1/K ic ), fluorescence quenching constant (K FQ ) and binding constant (K itc ) obtained from these measurements were compared and correlated to analyse the relations between PPA inhibition and binding behaviour. The role of the galloyl moiety in binding of catechins and theaflavins with PPA was highlighted as well. In addition, the effects of three soluble polysaccharides (citrus pectin (CP), wheat arabinoxylan (WAX) and oat β-glucan (OBG)) on the inhibition of PPA by tea polyphenols were studied through PPA inhibition, IC 50 value, inhibition kinetics and fluorescence quenching methods. Furthermore, the effects of tea polyphenols on binding of PPA with normal maize starch granules were studied in terms of binding ratio, dissociation constant (K d ) and binding rate. Then, the association constant (1/K d ), 1/K ic and K FQ of tea polyphenols were correlated to analyse the effects of PPA inhibition on the binding of the enzyme with starch.The results show that green, oolong and black tea extracts, epigallocatechin gallate, theaflavin-3, 3'-digallate and tannic acid were competitive inhibitors of PPA, whereas epicatechin gallate, theaflavin-3'-gallate and theaflavin were mixed-type inhibitors with both competitive and uncompetitive inhibitory characteristics. Only catechins with a galloyl substituent at the 3-position showed measurable inhibition. K ic values were lower for theaflavins than catechins, with the lowest value for theaflavin-3, 3'-digallate. The lower K ic than the uncompetitive inhibition constant for the mixed-type inhibitors suggests that they bind more tightly with free PPA than with the PPA-starch complex. A 3 and/or 3'-galloyl moiety in catechin and theaflavin structures was consistently found to increase inhibition of PPA through enhanced association with the enzyme active site. A higher quenching effect of polyphenols corresponded to a stronger inhibitory activity against PPA. The red-shift of maximum emission wavelength of PPA bound with some polyphenols indicated a potential IV

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The binding of α‐amylase to starch plays a decisive role in the initiation of storage starch degradation in turions of Spirodela polyrhiza

Cited by 12 publications

References 37 publications

Light‐induced degradation of storage starch in turions of Spirodela polyrhiza depends on nitrate

Light‐induced degradation of storage starch in turions of Spirodela polyrhiza depends on nitrate

Genetic structure of the genus Lemna L. (Lemnaceae) as revealed by amplified fragment length polymorphism

Studying the interactions between tea polyphenols and α-amylase

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