Any feedback?
Literature summary for 2.4.1.173 extracted from
- Purification and physico-kinetic characterization of 3beta-hydroxy specific sterol glucosyltransferase from Withania somnifera (L) and its stress response (2007), Biochim. Biophys. Acta, 1774, 392-402.
Activating Compound
| Activating Compound | Comment | Organism | Structure |
|---|---|---|---|
| Triton X-100 | up to 0.03% Triton X-100 in the assay mixture, the catalytic activity is enhanced | Withania somnifera |  |
Inhibitors
| Inhibitors | Comment | Organism | Structure |
|---|---|---|---|
| Co2+ | strongly inhibits the sterol glucosyltransferase activity, IC50 (mM): 1.3 | Withania somnifera | |
| GTP | the inhibitory effect of GTP is less prominent as compared to UDP | Withania somnifera | |
| Hg2+ | strongly inhibits the sterol glucosyltransferase activity, IC50 (mM): 0.5 | Withania somnifera | |
| iodoacetamide | strong and irreversible inhibition by thiol directed reagents like 4-chloromercuribenzoate, N-methylmaleimide and iodoacetamide suggest the requirement of free-SH groups for the catalytic activity | Withania somnifera | |
| N-ethylmaleimide | strong and irreversible inhibition by thiol directed reagents like 4-chloromercuribenzoate, N-methylmaleimide and iodoacetamide suggest the requirement of free-SH groups for the catalytic activity | Withania somnifera | |
| Ni2+ | strongly inhibits the sterol glucosyltransferase activity, IC50 (mM): 1.2 | Withania somnifera | |
| p-chloromercuribenzoate | strong and irreversible inhibition by thiol directed reagents like 4-chloromercuribenzoate, N-methylmaleimide and iodoacetamide suggest the requirement of free-SH groups for the catalytic activity | Withania somnifera | |
| Triton X-100 | at higher levels (0.3%), Triton X-100 inactivats the enzyme, giving 10% of the original activity after 30 min pre-incubation | Withania somnifera | |
| UDP | the inhibitory effect of UTP and GTP is less prominent as compared to UDP | Withania somnifera | |
| UTP | the inhibitory effect of UTP is less prominent as compared to UDP | Withania somnifera | |
| Zn2+ | strongly inhibits the sterol glucosyltransferase activity, IC50 (mM): 0.04 | Withania somnifera | |
KM Value [mM]
| KM Value [mM] | KM Value Maximum [mM] | Substrate | Comment | Organism | Structure |
|---|---|---|---|---|---|
| 0.002 | - |
diosgenin | for the cytosolic enzyme | Withania somnifera | |
| 0.005 | - |
pregnenolone | for the cytosolic enzyme | Withania somnifera | |
| 0.005 | - |
beta-sitosterol | for the cytosolic enzyme | Withania somnifera | |
| 0.006 | - |
3-beta-hydroxy-pregna-5,16-dien-20-one | for the cytosolic enzyme | Withania somnifera | |
| 0.014 | - |
UDP-glucose | for the cytosolic enzyme | Withania somnifera | |
| 0.024 | - |
24-methylene cholesterol | for the cytosolic enzyme | Withania somnifera | |
| 0.119 | - |
dehydroepiandrosterone | for the cytosolic enzyme | Withania somnifera | |
| 0.125 | - |
stigmasterol | for the cytosolic enzyme | Withania somnifera | |
Metals/Ions
| Metals/Ions | Comment | Organism | Structure |
|---|---|---|---|
| additional information | Mg2+, Mn2+, Ca2+, Co2+ do not show any effect | Withania somnifera |
Molecular Weight [Da]
| Molecular Weight [Da] | Molecular Weight Maximum [Da] | Comment | Organism |
|---|---|---|---|
| 37000 | - |
SDS-PAGE | Withania somnifera |
Organism
| Organism | UniProt | Comment | Textmining |
|---|---|---|---|
| Withania somnifera | - |
- |
- |
Purification (Commentary)
| Purification (Comment) | Organism |
|---|---|
| Cibacron Blue column, Sephadex G-25 column and Mono Q anion exchange column | Withania somnifera |
Source Tissue
| Source Tissue | Comment | Organism | Textmining |
|---|---|---|---|
| leaf | - |
Withania somnifera | - |
Specific Activity [micromol/min/mg]
| Specific Activity Minimum [µmol/min/mg] | Specific Activity Maximum [µmol/min/mg] | Comment | Organism |
|---|---|---|---|
| additional information | - |
the cytosolic enzyme shows 100% activity with 24-methylene chloseterol as substrate. Using Dehydroepiandrosterone, Stigmasterol, Brassicasterol, beta-sitosterol or Deacetyl-16-DPA the activtity is 75% - 44%. Using Diosgenin, Solasdine or Pregnenolene the activity is 31,5% - 14.1%. Using Cholesterol, 20S,22R-1alpha, 3beta-dihydroxy-witha-5,24-dienolide, Hecogenin, Tigogenin, Quercetin or Daidzein the activity is 8.9% - 2.1%. There is no activity, when using Euphol, Ursolic acid, Testosterone, Estradiol or Single glucose withanolide as substrate. Sterol glucosyltransferase activity is monitored radiometricaly using UDP-[U-14C] glucose as the radioactive substrate in the radioactive substrate | Withania somnifera |
| additional information | - |
the membrane bound enzyme shows 100% activity with 24-methylene chloseterol as substrate. Using Deacetyl-16-DPA, beta-sitosterol, Brassicasterol, Dehydroepiandrosterone, Pregnenolene, Stigmasterol or Cholesterol the activtity is 577% - 124%. The enzyme shows 2% activity with Diosgenin as substrate. It does not show any activity with Solasodine 16,17alpha-epoxy prednenolene, Hecogenin, 20S,22R-1alpha, 3beta-dihydroxy-witha-5,24-dienolide, Tigogenin, Quercetin, Daidzein, Euphol, Ursolic acid, Testosterone, Estradiol or Single glucose withanolide. | Withania somnifera |
Substrates and Products (Substrate)
| Substrates | Comment Substrates | Organism | Products | Comment (Products) | Rev. | Reac. |
|---|---|---|---|---|---|---|
| 24-methylene cholesterol + UDP-glucose | - |
Withania somnifera | UDP + 24-methylene-cholesterol 3-beta-D-glucoside | - |
? | |
| 3beta-hydroxy-pregna-5,16-dien-20-one + UDP-glucose | - |
Withania somnifera | UDP + 3beta-20-oxopregna-5,16-dien-3-yl beta-D-glucopyranoside | - |
? | |
| beta-sitosterol + UDP-glucose | - |
Withania somnifera | UDP + beta-sitosterol 3-beta-D-glucoside | - |
? | |
| dehydroepiandrosterone + UDP-glucose | - |
Withania somnifera | UDP + dehydroepiandrosterone 3-beta-D-glucoside | - |
? | |
| diosgenin + UDP-glucose | - |
Withania somnifera | UDP + diosgenin 3-beta-D-glucoside | - |
? | |
| additional information | the enzyme is highly specific to sterols and shows no activity with non steroidal substrates. Amongst the sterols, the enzyme is position specific and works only with C-3 hydroxyl sterols, but the extradiol C-3 hydroxyl group is not glucosylated. Sterols with A-B ring 5-en (e.g. deacetyl-16-DPA) are glucosylated more efficiently than those with 5alpha-H. For the cytosolic enzyme, the relative substrate specificity of the membrane-bound enzyme is different. The membrane enzyme is more specific towards phytosterols and brassicasterol. It shows no activity towards secondary metabolits and flavonoids and isoflavonoids. | Withania somnifera | ? | - |
? | |
| pregnenolone + UDP-glucose | - |
Withania somnifera | UDP + pregnenolone 3-beta-D-glucoside | - |
? | |
| stigmasterol + UDP-glucose | - |
Withania somnifera | UDP + stigmasterol 3-beta-D-glucoside | - |
? | |
Temperature Optimum [°C]
| Temperature Optimum [°C] | Temperature Optimum Maximum [°C] | Comment | Organism |
|---|---|---|---|
| 30 | - |
- |
Withania somnifera |
Turnover Number [1/s]
| Turnover Number Minimum [1/s] | Turnover Number Maximum [1/s] | Substrate | Comment | Organism | Structure |
|---|---|---|---|---|---|
| 0.0023 | - |
diosgenin | for the cytosolic enzyme | Withania somnifera | |
| 0.0037 | - |
beta-sitosterol | for the cytosolic enzyme | Withania somnifera | |
| 0.0047 | - |
pregnenolone | for the cytosolic enzyme | Withania somnifera | |
| 0.0072 | - |
dehydroepiandrosterone | for the cytosolic enzyme | Withania somnifera | |
| 0.0087 | - |
UDP-glucose | for the cytosolic enzyme | Withania somnifera | |
| 0.0088 | - |
stigmasterol | for the cytosolic enzyme | Withania somnifera | |
| 0.0093 | - |
3-beta-hydroxy-pregna-5,16-dien-20-one | for the cytosolic enzyme | Withania somnifera | |
| 0.38 | - |
24-methylene cholesterol | for the cytosolic enzyme | Withania somnifera | |
pH Optimum
| pH Optimum Minimum | pH Optimum Maximum | Comment | Organism |
|---|---|---|---|
| 8 | - |
- |
Withania somnifera |
pH Range
| pH Minimum | pH Maximum | Comment | Organism |
|---|---|---|---|
| 7 | 9 | the enzyme has an optimum pH for activity around 8.0 with half maximal activities at 7.0 and above 9.0 | Withania somnifera |
pI Value
| Organism | Comment | pI Value Maximum | pI Value |
|---|---|---|---|
| Withania somnifera | determined by chromatofocusing | - |
3.8 |
IC50 Value
| IC50 Value | IC50 Value Maximum | Comment | Organism | Inhibitor | Structure |
|---|---|---|---|---|---|
| 0.04 | - |
strongly inhibits the sterol glucosyltransferase activity, IC50 (mM): 0.04 | Withania somnifera | Zn2+ | |
| 0.5 | - |
strongly inhibits the sterol glucosyltransferase activity, IC50 (mM): 0.5 | Withania somnifera | Hg2+ | |
| 1.2 | - |
strongly inhibits the sterol glucosyltransferase activity, IC50 (mM): 1.2 | Withania somnifera | Ni2+ | |
| 1.3 | - |
strongly inhibits the sterol glucosyltransferase activity, IC50 (mM): 1.3 | Withania somnifera | Co2+ | |
Use of this online version of BRENDA is free under the CC BY 4.0 license. See terms of use for full details.
Release 2023.1 (January 2023)
Legal
Curated at
Member of
