The sugary-type isoamylase in wheat: tissue distribution and subcellular localisation

Genschel, Ulrich; Abel, Gernot; Lörz, Horst; Lütticke, Stephanie

doi:10.1007/s00425-001-0691-3

Cited by 17 publications

(7 citation statements)

References 26 publications

(35 reference statements)

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“…The low activity of Stisa1 or Stisa1/Stisa2 on whole starch suggests that in vivo the primary substrate for the Stisa1/Stisa2 complex is soluble branched glucan rather than any highly branched regions on the outside of starch granules. Similar conclusions were drawn for the activity of an isoamylase characterized recently in wheat (Genschel et al, 2002). The Stisa1 and Stisa3 isoforms also show interactions in their ability to debranch some substrates.…”

Section: Roles Of Stisa1 Stisa2 and Stisa3 In Starch Synthesissupporting

confidence: 63%

Three Isoforms of Isoamylase Contribute Different Catalytic Properties for the Debranching of Potato Glucans[W]

Mant²,

et al. 2003

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Isoamylases are debranching enzymes that hydrolyze ␣ -1,6 linkages in ␣ -1,4/ ␣ -1,6-linked glucan polymers. In plants, they have been shown to be required for the normal synthesis of amylopectin, although the precise manner in which they influence starch synthesis is still debated. cDNA clones encoding three distinct isoamylase isoforms (Stisa1, Stisa2, and Stisa3) have been identified from potato. The expression patterns of the genes are consistent with the possibility that they all play roles in starch synthesis. Analysis of the predicted sequences of the proteins suggested that only Stisa1 and Stisa3 are likely to have hydrolytic activity and that there probably are differences in substrate specificity between these two isoforms. This was confirmed by the expression of each isoamylase in Escherichia coli and characterization of its activity. Partial purification of isoamylase activity from potato tubers showed that Stisa1 and Stisa2 are associated as a multimeric enzyme but that Stisa3 is not associated with this enzyme complex. Our data suggest that Stisa1 and Stisa2 act together to debranch soluble glucan during starch synthesis. The catalytic specificity of Stisa3 is distinct from that of the multimeric enzyme, indicating that it may play a different role in starch metabolism.

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Section: Roles Of Stisa1 Stisa2 and Stisa3 In Starch Synthesissupporting

confidence: 63%

Three Isoforms of Isoamylase Contribute Different Catalytic Properties for the Debranching of Potato Glucans[W]

Mant²,

et al. 2003

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“…Studies on starch accumulation in wheat grain and related enzyme activities under drought stress have been reported [23,24]. The results on starch content indicate that drought stress caused a decrease in starch content in both the wheat varieties and higher decrease was observed in WH 1105 (5.7%) as compared to WH 1025 (4.2%) (Table 2).…”

Section: Discussionmentioning

confidence: 95%

The Effect of Drought Stress Treatment on Some Grain Quality Traits in Wheat (Triticum aestivum L.) Varieties

Rao

Raghavendra

Gill

et al. 2021

IJPSS

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Climate change imposes many environmental stresses out of which drought stress is a major concern that significantly restricts crop production in arid and semi-arid regions. The negative impact on grain quality caused by drought stress is responsible for reduced grain yield and quality. Many previous studies aimed to understand the tolerance level of wheat varieties, but studies on grain quality traits assessment were less. Therefore, the aim of the present investigation was to study some grain quality traits and to determine how drought stress affected these parameters. Experiments with two wheat varieties viz. WH 1105 and WH 1025 were conducted in microplots with RBD design in open fields. Grains were selected after harvest of the crop and were used to evaluate sedimentation value, β carotene, crude fibre, total sugars and starch. Sedimentation values (ml) were increased more in WH 1025 (6.9 per cent) than WH 1105 (3.8 per cent). Beta carotene content (µg g-1 DW), crude fibre (%), total sugar (%) and starch (%) contents were decreased in both wheat varieties and more decrease was observed in WH 1105 than WH 1025 under drought condition than irrigated condition. The study revealed that quality traits of WH 1105 were much affected than WH 1025 under drought stress.

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“…To the best of our knowledge, this is the first isolation of a DBE cDNA clone from bananas, even though it was a partial sequence. Attempts to isolate the missing 5′-region of the Maisa sequence by RACE were unsuccessful, probably because the banana sequence has a high G+C content at its 5'-end, similar to what was discussed for the sequences from rice endosperm (17) and wheat (25).…”

Section: Discussionmentioning

confidence: 97%

Activity, Cloning, and Expression of an Isoamylase-Type Starch-Debranching Enzyme from Banana Fruit

Bierhals

Lajolo

Cordenunsi

et al. 2004

J. Agric. Food Chem.

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Unripe bananas have a high content of starch (almost 20%) that is metabolized during fruit ripening with a concomitant synthesis of soluble sugars. Since starch granules are composed of amylose and amylopectin, several enzymes have to be involved in its mobilization during banana ripening, with a necessary participation of one starch-debranching enzyme (DBE) to hydrolyze the alpha-1,6-branches of amylopectin. Banana DBE seems to be an isoamylase-type enzyme, as indicated by substrate specificity and the cloning of a 1575 bp cDNA, similar to the isoamylase sequences from potato, Arabdopsis, and maize. The assays for DBE indicated only minor changes in activity during ripening, and the results of the northern and western blots with antiserum against the recombinant banana isoamylase were in agreement with the steady-state level of activity, since no significant changes in gene expression were observed. The high activity on beta-limit dextrin and the similarity to the potato isoform 3 suggest that during banana ripening the hydrolysis of alpha-1,6-linkage of amylopectin results from the activity of a pre-existing isoamylase-type debranching enzyme in coordination with other amylolitic enzymes. To the best of our knowledge, this is the first evaluation of activity and expression of a DBE from a fruit.

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The sugary-type isoamylase in wheat: tissue distribution and subcellular localisation

Cited by 17 publications

References 26 publications

Three Isoforms of Isoamylase Contribute Different Catalytic Properties for the Debranching of Potato Glucans[W]

Three Isoforms of Isoamylase Contribute Different Catalytic Properties for the Debranching of Potato Glucans[W]

The Effect of Drought Stress Treatment on Some Grain Quality Traits in Wheat (Triticum aestivum L.) Varieties

Activity, Cloning, and Expression of an Isoamylase-Type Starch-Debranching Enzyme from Banana Fruit

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