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Literature summary for 3.2.1.10 extracted from
- Comparison of sucrase-free isomaltase with sucrase-isomaltase purified from the house musk shrew Suncus murinus (2001), Biochim. Biophys. Acta, 1544, 341-349.
Protein Variants
| Protein Variants | Comment | Organism |
|---|---|---|
| additional information | the sucrase-free mutant lacks the entire sucrase domain and 69 amino acids of the C-terminus of isomaltase domain, the isomaltase function is unaffected by the mutation, sucrase function is missing | Suncus murinus |
KM Value [mM]
| KM Value [mM] | KM Value Maximum [mM] | Substrate | Comment | Organism | Structure |
|---|---|---|---|---|---|
| 7 | - |
maltose | wild-type sucrase-isomaltase | Suncus murinus |  |
| 12.8 | - |
isomaltose | wild-type sucrase-isomaltase | Suncus murinus | |
| 13.6 | - |
isomaltose | mutant isomaltase | Suncus murinus | |
| 27.5 | - |
sucrose | wild-type sucrase-isomaltase | Suncus murinus | |
| 62.8 | - |
maltose | mutant isomaltase | Suncus murinus | |
Localization
| Localization | Comment | Organism | GeneOntology No. | Textmining |
|---|---|---|---|---|
| membrane | - |
Suncus murinus | 16020 | - |
Molecular Weight [Da]
| Molecular Weight [Da] | Molecular Weight Maximum [Da] | Comment | Organism |
|---|---|---|---|
| 103000 | - |
1 * 103000, mutant sucrase-free isomaltase, SDS-PAGE | Suncus murinus |
| 106000 | - |
1 * 106000, isomaltase subunit of the wild-type enzyme, + 1 * 115000, sucrase subunit of the wild-type enzyme, SDS-PAGE | Suncus murinus |
| 115000 | - |
1 * 106000, isomaltase subunit of the wild-type enzyme, + 1 * 115000, sucrase subunit of the wild-type enzyme, SDS-PAGE | Suncus murinus |
Organism
| Organism | UniProt | Comment | Textmining |
|---|---|---|---|
| Suncus murinus | - |
house musk shrew, contains 2 enzyme forms: a sucrase-free isomaltase and a sucrase-isomaltase | - |
Posttranslational Modification
| Posttranslational Modification | Comment | Organism |
|---|---|---|
| glycoprotein | enzyme, especially the mutant enzyme, contains probably carbohydrates with terminal L-fucose, determined by lectin affinity, overview | Suncus murinus |
Purification (Commentary)
| Purification (Comment) | Organism |
|---|---|
| sucrase-free isomaltase and a sucrase-isomaltase from a wild-type and a sucrase-deficient mutant line, from intestine, by temperature adsorption-desorption affinity chromatography on Sephadex gel | Suncus murinus |
Source Tissue
| Source Tissue | Comment | Organism | Textmining |
|---|---|---|---|
| intestine | - |
Suncus murinus | - |
| mucosa | - |
Suncus murinus | - |
Specific Activity [micromol/min/mg]
| Specific Activity Minimum [µmol/min/mg] | Specific Activity Maximum [µmol/min/mg] | Comment | Organism |
|---|---|---|---|
| 2.12 | - |
purified mutant sucrase-free isomaltase, maltase activity | Suncus murinus |
| 7.79 | - |
purified wild-type sucrase-isomaltase, sucrase activity | Suncus murinus |
| 8.08 | - |
purified wild-type sucrase-isomaltase, isomaltase activity | Suncus murinus |
| 12.3 | - |
purified mutant sucrase-free isomaltase, isomaltase activity | Suncus murinus |
| 14.5 | - |
purified wild-type sucrase-isomaltase, maltase activity | Suncus murinus |
Substrates and Products (Substrate)
| Substrates | Comment Substrates | Organism | Products | Comment (Products) | Rev. | Reac. |
|---|---|---|---|---|---|---|
| amylose + H2O | n = 18, low activity of wild-type sucrase-isomaltase, very low activity of mutant isomaltase | Suncus murinus | ? | - |
? | |
| glycogen + H2O | substrate from oyster, low activity of wild-type sucrase-isomaltase, very low activity of mutant isomaltase | Suncus murinus | ? | - |
? | |
| isomaltose + H2O | best substrate for the mutant isomaltase | Suncus murinus | 2 D-glucose | - |
? | |
| maltoheptaose + H2O | low activity of mutant isomaltase | Suncus murinus | ? | - |
? | |
| maltohexaose + H2O | low activity of mutant isomaltase | Suncus murinus | ? | - |
? | |
| maltopentaose + H2O | - |
Suncus murinus | ? | - |
? | |
| maltose + H2O | best substrate of the wild-type sucrase-isomaltase | Suncus murinus | 2 D-glucose | - |
? | |
| maltotetraose + H2O | low activity of mutant isomaltase | Suncus murinus | ? | - |
? | |
| maltotriose + H2O | low activity of mutant isomaltase | Suncus murinus | ? | - |
? | |
| additional information | substrate specificities of mutant isomaltase and wild-type sucrase-isomaltase, overview | Suncus murinus | ? | - |
? | |
| pullulan + H2O | low activity | Suncus murinus | ? | - |
? | |
| soluble starch + H2O | low activity of wild-type sucrase-isomaltase, very low activity of mutant isomaltase | Suncus murinus | ? | - |
? | |
| sucrose + H2O | wild-type sucrase-isomaltase, no activity with the mutant isomaltase | Suncus murinus | D-glucose + D-fructose | - |
? | |
Subunits
| Subunits | Comment | Organism |
|---|---|---|
| dimer | 1 * 106000, isomaltase subunit of the wild-type enzyme, + 1 * 115000, sucrase subunit of the wild-type enzyme, SDS-PAGE | Suncus murinus |
| monomer | 1 * 103000, mutant sucrase-free isomaltase, SDS-PAGE | Suncus murinus |
Synonyms
| Synonyms | Comment | Organism |
|---|---|---|
| isomaltase | - |
Suncus murinus |
| sucrase-isomaltase | - |
Suncus murinus |
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