Protein Variants | Comment | Organism |
---|---|---|
F159Y | site-directed mutagenesis, pre-steadystate chemistry is reduced 32fold in mutant F159Y PNP. Pre-steady-state chemistry compares heavy and light molecular weight wild-type and mutant F159Y PNPs and finds a normal heavy-enzyme isotope effect of 1.31 for wild-type PNP and an inverse effect of 0.75 for F159Y mutant PNP. Increased isotopic mass in F159Y PNP causes more efficient transition state formation. Most heavy enzymes demonstrate normal heavy-enzyme isotope effects, and F159Y PNP is a rare example of an inverse effect | Homo sapiens |
KM Value [mM] | KM Value Maximum [mM] | Substrate | Comment | Organism | Structure |
---|---|---|---|---|---|
additional information | - |
additional information | steady-state Michaelis-Menten kinetics for the light- and heavy-isotope-labeled PNPs are measured for guanosine phosphorolysis, single-turnover pre-steady-state constants. Detailed isotope and kinetic analysis of wild-type an dmutant F159Y mutant enzymes, overview | Homo sapiens | |
0.0341 | - |
guanosine | pH 7.4, 25°C, wild-type light PNP | Homo sapiens | |
0.0399 | - |
guanosine | pH 7.4, 25°C, wild-type heavy PNP | Homo sapiens | |
0.0542 | - |
guanosine | pH 7.4, 25°C, mutant F159Y heavy PNP | Homo sapiens | |
0.0564 | - |
guanosine | pH 7.4, 25°C, mutant F159Y light PNP | Homo sapiens |
Natural Substrates | Organism | Comment (Nat. Sub.) | Natural Products | Comment (Nat. Pro.) | Rev. | Reac. |
---|---|---|---|---|---|---|
guanosine + phosphate | Homo sapiens | - |
guanine + alpha-D-ribose 1-phosphate | - |
r |
Organism | UniProt | Comment | Textmining |
---|---|---|---|
Homo sapiens | P00491 | - |
- |
Substrates | Comment Substrates | Organism | Products | Comment (Products) | Rev. | Reac. |
---|---|---|---|---|---|---|
guanosine + phosphate | - |
Homo sapiens | guanine + alpha-D-ribose 1-phosphate | - |
r |
Synonyms | Comment | Organism |
---|---|---|
PNP | - |
Homo sapiens |
purine nucleoside phosphorylase | - |
Homo sapiens |
Temperature Optimum [°C] | Temperature Optimum Maximum [°C] | Comment | Organism |
---|---|---|---|
25 | - |
assay at | Homo sapiens |
Turnover Number Minimum [1/s] | Turnover Number Maximum [1/s] | Substrate | Comment | Organism | Structure |
---|---|---|---|---|---|
7.8 | - |
guanosine | pH 7.4, 25°C, wild-type heavy PNP | Homo sapiens | |
8.3 | - |
guanosine | pH 7.4, 25°C, mutant F159Y heavy PNP | Homo sapiens | |
8.5 | - |
guanosine | pH 7.4, 25°C, mutant F159Y light PNP | Homo sapiens | |
8.7 | - |
guanosine | pH 7.4, 25°C, wild-type light PNP | Homo sapiens |
pH Optimum Minimum | pH Optimum Maximum | Comment | Organism |
---|---|---|---|
7.4 | - |
assay at | Homo sapiens |
General Information | Comment | Organism |
---|---|---|
malfunction | human genetic deficiency of PNP impairs expansion of activated T-cells as a consequence of the accumulation of dGTP specifically in activated T-cells. An unbalanced deoxynucleotide triphosphate pool leads to apoptotic cell death in the activated T-cell population, with no effect on quiescent T-cells. The inhibition of PNP is reported to be therapeutic in T-cell lymphoma and gout disease in clinical trials | Homo sapiens |
additional information | crystal structures and TPS dynamics of native and F159Y PNPs explore the catalytic-site geometry associated with these catalytic changes. Experimental validation of transition path-sampling (TPS) predictions for barrier crossing establishes the connection of rapid protein dynamics and vibrational coupling to enzymatic transition state passage | Homo sapiens |
physiological function | enzyme PNP provides the only metabolic pathway for the degradation of 2'-deoxyguanosine in human cells | Homo sapiens |
kcat/KM Value [1/mMs-1] | kcat/KM Value Maximum [1/mMs-1] | Substrate | Comment | Organism | Structure |
---|---|---|---|---|---|
150.7 | - |
guanosine | pH 7.4, 25°C, mutant F159Y light PNP | Homo sapiens | |
153.1 | - |
guanosine | pH 7.4, 25°C, mutant F159Y heavy PNP | Homo sapiens | |
195.5 | - |
guanosine | pH 7.4, 25°C, wild-type heavy PNP | Homo sapiens | |
255.1 | - |
guanosine | pH 7.4, 25°C, wild-type light PNP | Homo sapiens |