Protein Variants | Comment | Organism |
---|---|---|
D59A | replacement of putative acid/base catalyst, demonstration of the half-reaction with formation of sialyl-enzyme intermediate. Activity is restored by addition of azide and a sialyl azide product is formed | Trypanosoma cruzi |
KM Value [mM] | KM Value Maximum [mM] | Substrate | Comment | Organism | Structure |
---|---|---|---|---|---|
0.03 | - |
4-nitrophenyl alpha-sialoside | mutant D59A, hydrolysis, pH 7.6, 25°C | Trypanosoma cruzi | |
0.06 | - |
(trifluoromethyl)umbelliferyl alpha-sialoside | wild-type, hydrolysis, pH 7.6, 25°C | Trypanosoma cruzi | |
1.09 | - |
4-nitrophenyl alpha-sialoside | wild-type, hydrolysis, pH 7.6, 25°C | Trypanosoma cruzi |
Organism | UniProt | Comment | Textmining |
---|---|---|---|
Trypanosoma cruzi | - |
- |
- |
Reaction | Comment | Organism | Reaction ID |
---|---|---|---|
colominic acid + H2O = sialic acid + lactose | ping-pong bi-bi kinetic mechanism. Residue D59 functions as acid/base catalyst, and Y342 as active site nucleophile | Trypanosoma cruzi |
Substrates | Comment Substrates | Organism | Products | Comment (Products) | Rev. | Reac. |
---|---|---|---|---|---|---|
(trifluoromethyl)umbelliferyl alpha-sialoside + H2O | - |
Trypanosoma cruzi | (trifluoromethyl)umbelliferone + sialic acid | - |
? | |
(trifluoromethyl)umbelliferyl alpha-sialoside + lactose | - |
Trypanosoma cruzi | (trifluoromethyl)umbelliferone + sialyllactose | - |
? | |
4-nitrophenyl alpha-sialoside + H2O | - |
Trypanosoma cruzi | 4-nitrophenol + sialic acid | - |
? | |
4-nitrophenyl alpha-sialoside + lactose | - |
Trypanosoma cruzi | 4-nitrophenol + sialyllactose | - |
? | |
additional information | in addition to hydrolysis, enzyme catalyzes transglycosylation of sialyl residues to lactose. Km value and kcat value for sialyl transfer from 4-nitrophenyl alpha-sialoside are 5.8 mM and 6.77 per s, for sialyl transfer from (trifluoromethyl)umbelliferyl alpha-sialoside 0.26 mM and 15.7 per s, respectively | Trypanosoma cruzi | ? | - |
? |
Turnover Number Minimum [1/s] | Turnover Number Maximum [1/s] | Substrate | Comment | Organism | Structure |
---|---|---|---|---|---|
0.031 | - |
4-nitrophenyl alpha-sialoside | mutant D59A, hydrolysis, pH 7.6, 25°C | Trypanosoma cruzi | |
1.57 | - |
4-nitrophenyl alpha-sialoside | wild-type, hydrolysis, pH 7.6, 25°C | Trypanosoma cruzi | |
2.9 | - |
(trifluoromethyl)umbelliferyl alpha-sialoside | wild-type, hydrolysis, pH 7.6, 25°C | Trypanosoma cruzi |