Abstract
Barley beta-amylase undergoes proteolytic cleavage in the C-terminal region after germination. The implication of the cleavage in the enzyme's characteristics is unclear. With purified native beta-amylases from both mature barley grain and germinated barley, we found that the beta-amylase from germinated barley had significantly higher thermostability and substrate binding affinity for starch than that from mature barley grain. To better understand the effect of the proteolytic cleavage on the enzyme's thermostability and substrate binding affinity for starch, recombinant barley beta-amylases with specific deletions at the C-terminal tail were generated. The complete deletion of the four C-terminal glycine-rich repeats significantly increased the enzyme's thermostability, but an incomplete deletion with one repeat remaining did not change the thermostability. Although different C-terminal deletions affect the thermostability differently, they all increased the enzyme's affinity for starch. The possible reasons for the increased thermostability and substrate binding affinity, due to the removal of the four C-terminal glycine-rich repeats, are discussed in terms of the three-dimensional structure of beta-amylase.
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Claims 4
Claim · model-written summary
Beta-amylase from germinated barley had higher thermostability and starch binding affinity than that from mature barley grain.
- Taxon
- barley
.jpg?width=60)
Hordeum vulgaree1 - Treatment
- germinated barleye1
- Gene
- beta-amylasee1
- Outcome
- thermostability and substrate binding affinity for starche1
- Direction
- highere1
- Comparator
- mature barley graine1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
.jpg?width=500)
Verbatim
e1“the beta-amylase from germinated barley had significantly higher thermostability and substrate binding affinity for starch than that from mature barley grain”
Claim · model-written summary
Complete deletion of the four C-terminal glycine-rich repeats increased barley beta-amylase thermostability.
- Taxon
- barleyHordeum vulgaree0
- Treatment
- complete deletion of the four C-terminal glycine-rich repeatse2
- Gene
- beta-amylasee0
- Outcome
- thermostabilitye2
- Direction
- increasede2
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“recombinant barley beta-amylases with specific deletions at the C-terminal tail were generated”
e2“The complete deletion of the four C-terminal glycine-rich repeats significantly increased the enzyme's thermostability”
Claim · model-written summary
Incomplete deletion leaving one C-terminal repeat did not change barley beta-amylase thermostability.
- Taxon
- barleyHordeum vulgaree0
- Treatment
- incomplete deletion with one repeat remaininge3
- Gene
- beta-amylasee0
- Outcome
- thermostabilitye3
- Direction
- did not changee3
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“recombinant barley beta-amylases with specific deletions at the C-terminal tail were generated”
e3“an incomplete deletion with one repeat remaining did not change the thermostability”
Claim · model-written summary
C-terminal deletions increased barley beta-amylase affinity for starch.
- Taxon
- barleyHordeum vulgaree0
- Treatment
- C-terminal deletionse5
- Gene
- beta-amylasee0
- Outcome
- affinity for starche4
- Direction
- increasede4
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“recombinant barley beta-amylases with specific deletions at the C-terminal tail were generated”
e4“they all increased the enzyme's affinity for starch”
e5“different C-terminal deletions affect the thermostability differently”
The same questions in other papers
loss of function · quality: sugar starch · Hordeum vulgare (barley)Positive and negative results
3 in the opposite direction
- negative
- no effect
- negative
stage · quality: sugar starch · Hordeum vulgare (barley)Results agree
1 paper in the same direction as this paper
- positive
Claims are grouped by organism, treatment and what was measured or targeted. A paper counts as positive when any of its claims in the group is positive.