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Literature summary for 2.7.7.45 extracted from

  • Liu, J.J.; McLennan, A.G.
    Purification and properties of GTP:GTP guanylyltransferase from encysted embryos of the brine shrimp Artemia (1994), J. Biol. Chem., 269, 11787-11794.
    View publication on PubMed
Search for more literature for 2.7.7.45

Inhibitors

Inhibitors Comment Organism Structure
ITP partially uncompetitive inhibition of P1,P3-bis(5'-guanosyl)triphosphate synthesis Artemia sp.
XTP uncompetitive inhibition of P1,P4-bis(5'-guanosyl)tetraphosphate synthesis Artemia sp.

KM Value [mM]

KM Value [mM] KM Value Maximum [mM] Substrate Comment Organism Structure
6.7
-
 GTP pH 5.9, 43°C Artemia sp.

Molecular Weight [Da]

Molecular Weight [Da] Molecular Weight Maximum [Da] Comment Organism
80000
-
 2 * 142000, alpha + 2 * 80000, beta, SDS-PAGE Artemia sp.
142000
-
 2 * 142000, alpha + 2 * 80000, beta, SDS-PAGE Artemia sp.
480000
-
 gel filtration Artemia sp.

Natural Substrates/ Products (Substrates)

Natural Substrates Organism Comment (Nat. Sub.) Natural Products Comment (Nat. Pro.) Rev. Reac.
GTP + GTP Artemia sp. the structure and mechanism of this enzyme suggest an evolutionary relationship to mRNA capping enzymes diphosphate + P1,P4-bis(5'-guanosyl)tetraphosphate
-
 r

Organism

Organism UniProt Comment Textmining
Artemia sp.
-
-
-

Purification (Commentary)

Purification (Comment) Organism
1687fold to homogeneity Artemia sp.

Reaction

Reaction Comment Organism Reaction ID
2 GTP = diphosphate + P1,P4-bis(5'-guanosyl) tetraphosphate ping-pong kinetics with a covalent enzyme-guanylate intermediate containing a phosphoramidate linkage, probably phospholysine Artemia sp.
a

Source Tissue

Source Tissue Comment Organism Textmining
cyst
-
 Artemia sp.
-

Specific Activity [micromol/min/mg]

Specific Activity Minimum [µmol/min/mg] Specific Activity Maximum [µmol/min/mg] Comment Organism
0.113
-
 purified enzyme Artemia sp.

Substrates and Products (Substrate)

Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
5'-guanylylimidodiphosphate + diphosphate
-
 Artemia sp. GppNHppG + diphosphate
-
 ?
dGTP + dGTP
-
 Artemia sp. P1,P4-bis(5'-(2'-deoxyguanosyl) tetraphosphate + diphosphate
-
 r
GTP + GTP
-
 Artemia sp. P1,P4-bis(5'-guanosyl)tetraphosphate + diphosphate i.e. GP4G r
GTP + GTP
-
 Artemia sp. P1,P4-bis(5'-guanosyl)tetraphosphate + diphosphate certain phosphate analogs can substitute for diphosphate in the reverse reaction r
GTP + GTP the structure and mechanism of this enzyme suggest an evolutionary relationship to mRNA capping enzymes Artemia sp. diphosphate + P1,P4-bis(5'-guanosyl)tetraphosphate
-
 r
GTP + guanosine 5'-tetraphosphate
-
 Artemia sp. diguanosine 5',5'''-P1,P5-pentaphosphate + diphosphate i.e. GP5G r
GTP + ITP
-
 Artemia sp. GppppI + diphosphate
-
 r
GTP + XTP
-
 Artemia sp. GppppX + diphosphate
-
 r
P1,P4-bis(5'-guanosyl)tetraphosphate + carbonyldiphosphonate 29% of GTP-forming activity with diphosphate as second substrate Artemia sp. GTP + ?
-
 r
P1,P4-bis(5'-guanosyl)tetraphosphate + cyclotriphosphate 200% of GTP-forming activity with diphosphate as second substrate Artemia sp. GTP + ?
-
 r
P1,P4-bis(5'-guanosyl)tetraphosphate + methylenediphosphonate 25% of GTP-forming activity with diphosphate as second substrate Artemia sp. GTP + ?
-
 r
P1,P4-bis(5'-guanosyl)tetraphosphate + tripolyphosphate 75% of GTP-forming activity with diphosphate as second substrate Artemia sp. GTP + ?
-
 r

Subunits

Subunits Comment Organism
tetramer 2 * 142000, alpha + 2 * 80000, beta, SDS-PAGE Artemia sp.

Temperature Optimum [°C]

Temperature Optimum [°C] Temperature Optimum Maximum [°C] Comment Organism
43
-
 assay at Artemia sp.

Turnover Number [1/s]

Turnover Number Minimum [1/s] Turnover Number Maximum [1/s] Substrate Comment Organism Structure
1.2
-
 GTP
-
 Artemia sp.
1.6
-
 GTP
-
 Artemia sp.

pH Optimum

pH Optimum Minimum pH Optimum Maximum Comment Organism
5.9
-
 assay at Artemia sp.