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The two reactions compared are done so using a Tanimoto similarity score (for more information, please see the MACiE FAQ) for the bond changes only. The score maay range from 0 to 1 where 1 indicates that the two reactions are identical at the bond change level and 0 indicates that there are no bond changes in common.


Key

1.0-0.9 0.9-0.8 0.8-0.7 0.7-0.6 0.6-0.5 0.5-0.4 0.4-0.3 0.3-0.2 0.2-0.1 0.1-0.0 =0

Results for Comparison of M0237 and M0227

These two reactions have a combined similarity of 0.45


M0237

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Comparison

M0227

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EC 1.5.1.33
pteridine reductase
Sub-Class EC 1.1.1.271
GDP-L-fucose synthase

Image of NADPH

Image of Biopterin

Image of Proton

right arrow

Image of NADP+

Image of Tetrahydrobiopterin

2 NADPH
C00005
CHEBI:16474
Biopterin
C06313
CHEBI:15373
2 Proton
C00080
CHEBI:24636
2 NADP+
C00006
CHEBI:18009
Tetrahydrobiopterin
C00272
CHEBI:52447
0.32

Image of NADPH

Image of GDP-4-dehydro-6-deoxy-D-mannose

Image of Proton

right arrow

Image of NADP

Image of GDP-L-fucose

NADPH
C00005
CHEBI:16474
GDP-4-dehydro-6-deoxy-D-mannose
C01222
CHEBI:16955
Proton
C00080
CHEBI:24636
NADP
C00006
CHEBI:18009
GDP-L-fucose
C14830
CHEBI:17009

Catalytic CATH Codes

3.40.50.720

Catalytic CATH Codes

3.40.50.720
3.90.25.10

Active Site



0.09

Active Site



Catalytic Residues

Type Number Chain Location of Function
Arg 14 A Side Chain
Asp 161 A Side Chain
Tyr 174 A Side Chain
0.1

Catalytic Residues

Type Number Chain Location of Function
Tyr 136 A Side Chain
Lys 140 A Side Chain
Ser 107 A Side Chain
Ser 108 A Side Chain
Cys 109 A Side Chain
His 179 A Side Chain

Organic Cofactors

No Associated Organic Cofactors

Organic Cofactors

No Associated Organic Cofactors

Metal Cofactors

No Associated Metal Cofactors

Metal Cofactors

No Associated Metal Cofactors

Reaction occurs across 3 steps

0.6097

Reaction occurs across 6 steps

Step 1
GIF of Reaction Step M0237.stg01

NADPH transfers a hydride to the C7 position of biopterin. The N8 position is protonated by Tyr174, which in turn is protonated by Asp161. Since Asp161 is exposed to the bulk solvent it is then protonated by water.
0.47 Step 1
GIF of Reaction Step M0227.stg01

His179 initiates a keto-enol tautomerisation by removing the C3 proton of the substrate, forming an enolic intermediate and resulting in concomitant protonation of the C4 oxygen by Tyr136.
Step 2
GIF of Reaction Step M0237.stg02

The dihydrobiopterin intermediate tautomerises.
0.25 Step 2
GIF of Reaction Step M0227.stg02

Tyr136 initiates a keto-enol tautomerisation by removing the O4 proton, forming the keto form and protonation of C3 by His179 completes the epimerisation of the substrate, i.e. the proton is added to the opposite side of the ring from which it was removed.
Step 3
GIF of Reaction Step M0237.stg03

NADPH transfers a hydride to the C6 position of the dihydrobiopterin intermediate. The N5 position is protonated by an activated water. This water then deprotonates the 4-hydroxyl group and causes tautomerisation back to the keto-form.
0.37 Step 3
GIF of Reaction Step M0227.stg03

His179 removes the C5 proton leading to the formation of an enolic intermediate and protonation of the C4 oxygen by Tyr136.
Step 4
No Step with this number present
N/A Step 4
GIF of Reaction Step M0227.stg04

Tyr136 deprotonates the substrate at O4 leading to the formation of the keto form and protonation of C5 by His179. This proton is added on the opposite side of the ring from which it was removed.
Step 5
No Step with this number present
N/A Step 5
GIF of Reaction Step M0227.stg05

NADPH transfers a hydride from its C4 position to the C4 position of the sugar. The resulting alkoxide is protonated by Tyr136, which is in turn protonated by Ser107.
Step 6
No Step with this number present
N/A Step 6
GIF of Reaction Step M0227.stg06

Inferred return step in which Ser107 is re-protonated by water.

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