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US 2020/0347377 A1Published application
Ketose 3-epimerase with improved thermal stability
AssigneeMatsutani Chemical Industry Co., Ltd.
InventorsKouhei OHTANI, Kazuhiko ISHIKAWA, Masako NAKAMURA, Kazutaka KATSUKI
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Abstract
It is found that a variant enzyme with an improved thermal stability can be obtained by substituting a specific amino acid in the amino acid sequence of a ketose 3-epimerase originated from Arthrobacter globiformis and that D-psicose can be efficiently produced.
Claims4
1-10. (canceled)
A variant of ketose 3-epimerase of SEQ ID NO:
- 1, said variant being characterized by the following (a) and (b):
- (a) comprising a substitution at 1-8 amino acid residue positions compared to the sequence of SEQ ID NO:
- 1, said substitution being selected from the following:
- Ketose
- 3-epimerase
- variant
- Substitution in Amino Acid Sequence of SEQ ID NO:
- 1
- PM4
- S137C and N173C
- PM17
- H271C and D278C
- PM18
- S67P, D68A, A69D and T70G
- PM23
- R160A and H289X1 (X1 = VSARHKP (SEQ ID NO:
- 2))
- PM26
- R160A, H271C, D278C and H289X1 (X1 = VSARHKP
- (SEQ ID NO:
- 2))
- PM28
- S22T, S67P, D68A, A69D, T70G, R160A and H289X1
- (X1 = VSARHKP (SEQ ID NO:
- 2))
- PM29
- S22T, S67P, D68A, A69D, T70G, R160A, H177M and
- H289X2 (X2 = VSARHKP (SEQ ID NO:
- 2))
- PM32
- D278F
- PM33
- A200L
- PM38
- V237I
- PM39
- A200K
- PM41
- F275C and D278C
- PM43
- H177M, A200K, V237I, F275C and D278C
- PM44
- E75P
- PM45
- T100P and D101V
- PM48
- R160A and H289X2 (X2 = VSAR (SEQ ID NO:
- 3))
- PM51
- E75P, H177M and V237I
- PM55
- R160A and H289X3 (X3 = VSARHK (SEQ ID NO:
- 4))
- PM56
- H6Y and H177M
- PM57
- M110W and H177M
- PM58
- S67P, A69D and T70G
- PM59
- S22T and V34I
- PM60
- D278L
- PM61
- V237L
- PM62
- V91I
- PM63
- A95R
- PM64
- S137K
- PM65
- A270K,
- (b) exhibiting a residual enzyme activity A at 50° C. after having been treated at 60° C. for 1 hour in 50 mM phosphate buffer (pH 8.0, containing 2 mM magnesium sulfate) suspension when an activity of untreated enzyme at 50° C. is set to 100, higher than that of wild-type ketose 3-epimerase of SEQ ID NO:
- 1 measured under same condition, and/or exhibiting a ratio of the activity at 70° C. (t70) to that at 50° C. (t50), expressed as t70/t50, higher than that of wild-type ketose 3-epimerase of SEQ ID NO:
- 1.
73 more elements
Dependencies are inferred from the claim text.