Information on EC 2.4.2.44 - S-methyl-5'-thioinosine phosphorylase

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The expected taxonomic range for this enzyme is: Pseudomonas aeruginosa

EC NUMBER
COMMENTARY
2.4.2.44
-
RECOMMENDED NAME
GeneOntology No.
S-methyl-5'-thioinosine phosphorylase
-
REACTION
REACTION DIAGRAM
COMMENTARY
ORGANISM
UNIPROT ACCESSION NO.
LITERATURE
S-methyl-5'-thioinosine + phosphate = hypoxanthine + S-methyl-5-thio-alpha-D-ribose 1-phosphate
show the reaction diagram
-
-
-
-
PATHWAY
KEGG Link
MetaCyc Link
S-methyl-5'-thioadenosine degradation III
-
SYSTEMATIC NAME
IUBMB Comments
S-methyl-5'-thioinosine:phosphate S-methyl-5-thio-alpha-D-ribosyl-transferase
No activity with S-methyl-5'-thioadenosine. The catabolism of of 5'-methylthioadenosine in Pseudomonas aeruginosa involves deamination to S-methyl-5'-thioinosine (EC 3.5.4.31, S-methyl-5'-thioadenosine deaminase) and phosphorolysis to hypoxanthine [1].
SYNONYMS
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
methylthioinosine phosphorylase
Q9HZK1
-
MTI phosphorylase
Q9HZK1
-
PA3004
Q9HZK1
gene name
ORGANISM
COMMENTARY
LITERATURE
SEQUENCE CODE
SEQUENCE DB
SOURCE
SUBSTRATE
PRODUCT                      
REACTION DIAGRAM
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
(Substrate)
LITERATURE
(Substrate)
COMMENTARY
(Product)
LITERATURE
(Product)
Reversibility
r=reversible
ir=irreversible
?=not specified
5'-methylthioinosine + phosphate
hypoxanthine + 5-methylthio-D-ribose 1-phosphate
show the reaction diagram
-, Q9HZK1
-
-
-
?
adenosine + phosphate
adenine + alpha-D-ribose 1-phosphate
show the reaction diagram
-, Q9HZK1
weak substrate
-
-
?
adenosine + phosphate
adenine + D-ribose 1-phosphate
show the reaction diagram
-, Q9HZK1
-
-
-
?
inosine + phosphate
hypoxanthine + alpha-D-ribose 1-phosphate
show the reaction diagram
-, Q9HZK1
the catalytic efficiency (kcat/Km) for S-methyl-5'-thioinosine is 290 times larger than for inosine
-
-
?
S-methyl-5'-thioinosine + phosphate
hypoxanthine + S-methyl-5-thio-alpha-D-ribose 1-phosphate
show the reaction diagram
-, Q9HZK1
the enzyme is involved in catabolism of 5'-methylthioadenosine in Pseudomonas aeruginosa. S-Methyl-5'-thioadenosine is converted to S-methyl-5'-thioinosine and hypoxanthine but not to adenine
-
-
?
S-methyl-5'-thioinosine + phosphate
hypoxanthine + S-methyl-5-thio-alpha-D-ribose 1-phosphate
show the reaction diagram
-, Q9HZK1
the methylthio group of S-methyl-5'-thioinosine is important for both substrate binding and catalysis
-
-
?
inosine + phosphate
hypoxanthine + D-ribose 1-phosphate
show the reaction diagram
-, Q9HZK1
-
-
-
?
additional information
?
-
-, Q9HZK1
S-methyl-5'-thioadenosine is not a substrate
-
-
-
NATURAL SUBSTRATES
NATURAL PRODUCTS
REACTION DIAGRAM
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
(Substrate)
LITERATURE
(Substrate)
COMMENTARY
(Product)
LITERATURE
(Product)
REVERSIBILITY
r=reversible
ir=irreversible
?=not specified
S-methyl-5'-thioinosine + phosphate
hypoxanthine + S-methyl-5-thio-alpha-D-ribose 1-phosphate
show the reaction diagram
-, Q9HZK1
the enzyme is involved in catabolism of 5'-methylthioadenosine in Pseudomonas aeruginosa. S-Methyl-5'-thioadenosine is converted to S-methyl-5'-thioinosine and hypoxanthine but not to adenine
-
-
?
INHIBITORS
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
IMAGE
5'-methylthio-4'-deaza-1'-aza-2'-deoxy-1'-(9-methylene)-immucillin-H
-, Q9HZK1
-
-
5'-methylthio-immucillin-H
-, Q9HZK1
-
-
5'-phenylthio-immucillin-H
-, Q9HZK1
-
-
S-methyl-5'-thioadenosine
-, Q9HZK1
competitive inhibitor
KM VALUE [mM]
KM VALUE [mM] Maximum
SUBSTRATE
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
IMAGE
0.0026
-
5'-methylthioinosine
-, Q9HZK1
pH 7.4, 25C
0.023
-
adenine
-, Q9HZK1
pH 7.4, 25C
0.023
-
adenosine
-, Q9HZK1
pH 7.4, 25C
0.09
-
Inosine
-, Q9HZK1
pH 7.4, 25C
0.0026
-
S-methyl-5'-thioinosine
-, Q9HZK1
pH 7.4, 25C
TURNOVER NUMBER [1/s]
TURNOVER NUMBER MAXIMUM[1/s]
SUBSTRATE
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
IMAGE
4.8
-
5'-methylthioinosine
-, Q9HZK1
pH 7.4, 25C
0.0549
-
adenine
-, Q9HZK1
pH 7.4, 25C
0.0549
-
adenosine
-, Q9HZK1
pH 7.4, 25C
0.57
-
Inosine
-, Q9HZK1
pH 7.4, 25C
4.8
-
S-methyl-5'-thioinosine
-, Q9HZK1
pH 7.4, 25C
kcat/KM VALUE [1/mMs-1]
kcat/KM VALUE [1/mMs-1] Maximum
SUBSTRATE
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
IMAGE
0.24
-
adenine
-, Q9HZK1
pH 7.4, 25C
6389
6.3
-
Inosine
-, Q9HZK1
pH 7.4, 25C
11674
1846
-
S-methyl-5'-thioinosine
-, Q9HZK1
pH 7.4, 25C
302329
Ki VALUE [mM]
Ki VALUE [mM] Maximum
INHIBITOR
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
IMAGE
0.00000034
-
5'-methylthio-4'-deaza-1'-aza-2'-deoxy-1'-(9-methylene)-immucillin-H
-, Q9HZK1
pH 7.4, 25C
-
0.0000008
-
5'-methylthio-4'-deaza-1'-aza-2'-deoxy-1'-(9-methylene)-immucillin-H
-, Q9HZK1
pH 7.4, 25C
-
0.000000076
-
5'-methylthio-immucillin-H
-, Q9HZK1
pH 7.4, 25C
-
0.00000084
-
5'-methylthio-immucillin-H
-, Q9HZK1
pH 7.4, 25C
-
0.000000035
-
5'-phenylthio-immucillin-H
-, Q9HZK1
pH 7.4, 25C
-
0.00000066
-
5'-phenylthio-immucillin-H
-, Q9HZK1
pH 7.4, 25C
-
0.07
-
S-methyl-5'-thioadenosine
-, Q9HZK1
pH 7.4, 25C
pH OPTIMUM
pH MAXIMUM
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
7.4
-
-, Q9HZK1
assay at
TEMPERATURE OPTIMUM
TEMPERATURE OPTIMUM MAXIMUM
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
25
-
-, Q9HZK1
assay at
PDB
SCOP
CATH
ORGANISM
Pseudomonas aeruginosa (strain ATCC 15692 / PAO1 / 1C / PRS 101 / LMG 12228)
SUBUNITS
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
homotrimer
-, Q9HZK1
crystal structure
trimer
-, Q9HZK1
the crystal structure in complex with hypoxanthine, determined to 2.8 A resolution reveals a 3-fold symmetric homotrimer
Crystallization/COMMENTARY
ORGANISM
UNIPROT ACCESSION NO.
LITERATURE
crystallization of recombinant enzyme (9 mg/ml) in 50 mM HEPES, pH 7.4, 30% polyethylene glycol monomethyl ether 2000, 0.1 M potassium thiocyanate in the presence of 5 mM S-methyl-5'-thioinosine and 5 mM sulfate by sitting-drop vapor diffusion. Crystal structure of the enzyme in complex with hypoxanthine is determined to 2.8 A resolution; the crystal structure of P. aeruginosa MTIP (PaMTIP) in complex with hypoxanthine is determined to 2.8 A resolution and reveals a three-fold symmetric homotrimer
-, Q9HZK1
Purification/COMMENTARY
ORGANISM
UNIPROT ACCESSION NO.
LITERATURE
Cloned/COMMENTARY
ORGANISM
UNIPROT ACCESSION NO.
LITERATURE
; expressed in Escherichia coli as a His-tagged fusion protein
-, Q9HZK1