Cloned (Comment) | Organism |
---|---|
CBS gene encoding the truncated yCBS (residues 1-353), lacking the regulatory domain, is expressed with a C-terminal, 6-His affinity tag in Escherichia coli | Saccharomyces cerevisiae |
Protein Variants | Comment | Organism |
---|---|---|
S289A | kcat/Km (L-serine) is reduced by 800fold compared to wild-type. Km (L-homocysteine) equal to wild-type, Km (L-serine) increased compared to wild-type. The reverse-reaction (L-cystathionine hydrolysis) shows a 1400fold reduction of kcat/Km (L-cystathionine) for mutant S289A which is dominated by a 230fold decrease in kcat. Residue S289 is essential in maintaining the properties and orientation of the pyridine ring of the pyridoxal 5'-phosphate cofactor. The reduction in activity of mutant S289A suggests that yeast CBS catalyzes the alpha, beta-elimination of L-Ser via an E1cB mechanism | Saccharomyces cerevisiae |
S289D | mutant shows no beta-replacement activity. Fluorescence energy transfer between tryptophan residue(s) of the enzyme and the pyridoxal 5'-phosphate cofactor, observed in the wild-type enzyme and diminished in the S289A mutant, is absent in S289D | Saccharomyces cerevisiae |
KM Value [mM] | KM Value Maximum [mM] | Substrate | Comment | Organism | Structure |
---|---|---|---|---|---|
0.14 | - |
L-cystathionine | reverse reaction (L-cystathionine hydrolysis), wild-type | Saccharomyces cerevisiae | |
0.16 | - |
L-homocysteine | mutant S289A | Saccharomyces cerevisiae | |
0.21 | - |
L-homocysteine | wild-type | Saccharomyces cerevisiae | |
0.7 | - |
L-serine | wild-type | Saccharomyces cerevisiae | |
0.9 | - |
L-cystathionine | reverse reaction (L-cystathionine hydrolysis), mutant S289A | Saccharomyces cerevisiae | |
27.1 | - |
L-serine | mutant S289A | Saccharomyces cerevisiae |
Organism | UniProt | Comment | Textmining |
---|---|---|---|
Saccharomyces cerevisiae | - |
- |
- |
Purification (Comment) | Organism |
---|---|
using Ni-NTA chromatography | Saccharomyces cerevisiae |
Substrates | Comment Substrates | Organism | Products | Comment (Products) | Rev. | Reac. |
---|---|---|---|---|---|---|
L-cysteine + L-homocysteine | - |
Saccharomyces cerevisiae | L-cystathionine + H2S | - |
r | |
L-serine + L-homocysteine | - |
Saccharomyces cerevisiae | ? | - |
r |
Subunits | Comment | Organism |
---|---|---|
dimer | - |
Saccharomyces cerevisiae |
Synonyms | Comment | Organism |
---|---|---|
CBS | - |
Saccharomyces cerevisiae |
cystathionine beta-synthase | - |
Saccharomyces cerevisiae |
Temperature Optimum [°C] | Temperature Optimum Maximum [°C] | Comment | Organism |
---|---|---|---|
37 | - |
assay at | Saccharomyces cerevisiae |
Turnover Number Minimum [1/s] | Turnover Number Maximum [1/s] | Substrate | Comment | Organism | Structure |
---|---|---|---|---|---|
0.0045 | - |
L-cystathionine | reverse reaction (L-cystathionine hydrolysis), mutant S289A | Saccharomyces cerevisiae | |
0.85 | - |
L-serine | cosubstrate: L-homocysteine, mutant S289A | Saccharomyces cerevisiae | |
0.85 | - |
L-homocysteine | cosubstrate: L-serine, mutant S289A | Saccharomyces cerevisiae | |
1.03 | - |
L-cystathionine | reverse reaction (L-cystathionine hydrolysis), wild-type | Saccharomyces cerevisiae | |
17 | - |
L-serine | cosubstrate: L-homocysteine, wild-type | Saccharomyces cerevisiae | |
17 | - |
L-homocysteine | cosubstrate: L-serine, wild-type | Saccharomyces cerevisiae |
pH Optimum Minimum | pH Optimum Maximum | Comment | Organism |
---|---|---|---|
8.6 | - |
assay at | Saccharomyces cerevisiae |
Cofactor | Comment | Organism | Structure |
---|---|---|---|
pyridoxal 5'-phosphate | - |
Saccharomyces cerevisiae |
kcat/KM Value [1/mMs-1] | kcat/KM Value Maximum [1/mMs-1] | Substrate | Comment | Organism | Structure |
---|---|---|---|---|---|
0.005 | - |
L-cystathionine | reverse reaction (L-cystathionine hydrolysis), mutant S289A | Saccharomyces cerevisiae | |
0.031 | - |
L-serine | mutant S289A | Saccharomyces cerevisiae | |
6.3 | - |
L-homocysteine | mutant S289A | Saccharomyces cerevisiae | |
7.5 | - |
L-cystathionine | reverse reaction (L-cystathionine hydrolysis), wild-type | Saccharomyces cerevisiae | |
25 | - |
L-serine | wild-type | Saccharomyces cerevisiae | |
80 | - |
L-homocysteine | wild-type | Saccharomyces cerevisiae |