Characterization of a Novel Thermostable O -Acetylserine Sulfhydrylase from Aeropyrum pernix K1
| Autor: | Kazuhiko Ishikawa, Koshiki Mino |
|---|---|
| Rok vydání: | 2003 |
| Předmět: |
Sulfide
Stereochemistry Archaeal Proteins Dimer Molecular Sequence Data Sulfides medicine.disease_cause Microbiology Dithiothreitol Substrate Specificity chemistry.chemical_compound Cystathionine Reaction rate constant Enzyme Stability Serine medicine Aeropyrum pernix Amino Acid Sequence Cysteine Homocysteine Molecular Biology Escherichia coli Pyridoxal chemistry.chemical_classification Cysteine Synthase Binding Sites Sequence Homology Amino Acid biology Desulfurococcaceae Temperature Hydrogen-Ion Concentration biology.organism_classification Enzymes and Proteins Enzyme Activation Kinetics Enzyme chemistry Biochemistry |
| Zdroj: | Journal of Bacteriology. 185:2277-2284 |
| ISSN: | 1098-5530 0021-9193 |
| Popis: | An O -acetylserine sulfhydrylase (OASS) from the hyperthermophilic archaeon Aeropyrum pernix K1, which shares the pyridoxal 5′-phosphate binding motif with both OASS and cystathionine β-synthase (CBS), was cloned and expressed by using Escherichia coli Rosetta(DE3). The purified protein was a dimer and contained pyridoxal 5′-phosphate. It was shown to be an enzyme with CBS activity as well as OASS activity in vitro. The enzyme retained 90% of its activity after a 6-h incubation at 100°C. In the O -acetyl- l -serine sulfhydrylation reaction, it had a pH optimum of 6.7, apparent K m values for O -acetyl- l -serine and sulfide of 28 and below 0.2 mM, respectively, and a rate constant of 202 s −1 . In the l -cystathionine synthetic reaction, it showed a broad pH optimum in the range of 8.1 to 8.8, apparent K m values for l -serine and l -homocysteine of 8 and 0.51 mM, respectively, and a rate constant of 0.7 s −1 . A. pernix OASS has a high activity in the l -cysteine desulfurization reaction, which produces sulfide and S -(2,3-hydroxy-4-thiobutyl)- l -cysteine from l -cysteine and dithiothreitol. |
| Databáze: | OpenAIRE |
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