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Literature summary for 3.2.2.25 extracted from

  • Negishi, O.; Ozawa, T.; Imagawa, H.
    N-methyl nucleosidase from tea leaves (1988), Agric. Biol. Chem., 52, 169-175.
No PubMed abstract available

Inhibitors

Inhibitors Comment Organism Structure
7-Methylhypoxanthine 50% inhibition at 5 mM, no inhibition at 1 mM Camellia sinensis
7-methylxanthine 40% inhibition at 5 mM, no inhibition at 1 mM Camellia sinensis
Ca2+ slight inhibition Camellia sinensis
Cu2+ slight inhibition Camellia sinensis
EDTA 90 inhibition at 1 mM Camellia sinensis
additional information no inhibitin by Mg2+, Fe2+, Co2+, NaF, and iodoacetate Camellia sinensis
PCMB 80% inhibition at 0.5 mM Camellia sinensis
Zn2+ slight inhibition Camellia sinensis

Molecular Weight [Da]

Molecular Weight [Da] Molecular Weight Maximum [Da] Comment Organism
55000
-
gel filtration Camellia sinensis

Natural Substrates/ Products (Substrates)

Natural Substrates Organism Comment (Nat. Sub.) Natural Products Comment (Nat. Pro.) Rev. Reac.
7-methylxanthosine + H2O Camellia sinensis second step in caffeine biosynthesis, pathway overview 7-methylxanthine + D-ribose
-
ir

Organism

Organism UniProt Comment Textmining
Camellia sinensis
-
-
-

Purification (Commentary)

Purification (Comment) Organism
native enzyme from leaves, separated from adenosine nucleosidase, EC 3.2.2.7, by anion exchange chromatography, followed by hydroxylapatite chromatography and gel filtration, to homogeneity Camellia sinensis

Source Tissue

Source Tissue Comment Organism Textmining
leaf
-
Camellia sinensis
-

Specific Activity [micromol/min/mg]

Specific Activity Minimum [µmol/min/mg] Specific Activity Maximum [µmol/min/mg] Comment Organism
0.00656
-
partially purified enzyme, after anion exchange chromatography Camellia sinensis
0.0294
-
purified enzyme Camellia sinensis

Substrates and Products (Substrate)

Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
1-methyladenosine + H2O 22% of the activity with 7-methylxanthosine, substrate as 7-methyladenosine perchlorate Camellia sinensis 1-methyladenine + D-ribose
-
ir
1-methylinosine + H2O 9% of the activity with 7-methylxanthosine Camellia sinensis 1-methylhypoxanthine + D-ribose
-
ir
1-methylxanthosine + H2O 12% of the activity with 7-methylxanthosine Camellia sinensis 1-methylxanthine + D-ribose
-
ir
3-methyladenosine + H2O 178% of the activity with 7-methylxanthosine, substrate as 3-methyladenosine p-toluenesulfonate Camellia sinensis 3-methyladenine + D-ribose
-
ir
3-methylguanosine + H2O 38% of the activity with 7-methylxanthosine Camellia sinensis 3-methylguanine + D-ribose
-
ir
3-methylinosine + H2O 128% of the activity with 7-methylxanthosine Camellia sinensis 3-methylhypoxanthine + D-ribose
-
ir
3-methylxanthosine + H2O 198% of the activity with 7-methylxanthosine Camellia sinensis 3-methylxanthine + D-ribose
-
ir
7-methyladenosine + H2O 13% of the activity with 7-methylxanthosine Camellia sinensis 7-methyladenine + D-ribose
-
ir
7-methylguanosine + H2O 189% of the activity with 7-methylxanthosine Camellia sinensis 7-methylguanine + D-ribose
-
ir
7-methylinosine + H2O 121% of the activity with 7-methylxanthosine Camellia sinensis 7-methylhypoxanthine + D-ribose
-
ir
7-methylxanthosine + H2O second step in caffeine biosynthesis, pathway overview Camellia sinensis 7-methylxanthine + D-ribose
-
ir
7-methylxanthosine + H2O the reverse reaction is catalyzed by a nucleoside phosphorylase using ribose-1-phosphate, overview Camellia sinensis 7-methylxanthine + D-ribose
-
ir
additional information substrate specificity, overview, no activity with 1-methylguanosine and guanosine, poor activity with inosine and adenosine Camellia sinensis ?
-
?

Synonyms

Synonyms Comment Organism
N-MeNase
-
Camellia sinensis

Temperature Optimum [°C]

Temperature Optimum [°C] Temperature Optimum Maximum [°C] Comment Organism
37
-
assay at Camellia sinensis

pH Optimum

pH Optimum Minimum pH Optimum Maximum Comment Organism
8 8.5
-
Camellia sinensis

pH Stability

pH Stability pH Stability Maximum Comment Organism
additional information
-
the purified enzyme is unstable in acidic medium Camellia sinensis