Details
| Original language | English |
|---|---|
| Pages (from-to) | 111-119 |
| Number of pages | 9 |
| Journal | Journal of plant physiology |
| Volume | 159 |
| Issue number | 2 |
| Publication status | Published - 1 Jan 2002 |
Abstract
So far, 7 different genes of the β-substituted alanine synthase family coding for proteins with O-acetyl-L-serine(thiol)lyase activity (OAS-TL) have been identified in Arabidopsis. The differences with respect to function and regulation of these isoforms are not well understood. In the present work, we aimed to differentiate between three OAS-TL proteins, A, B, and C, which are presumably localized in the cytoplasm, in plastids, and in mitochondria, respectively. The mature proteins were expressed in E. coli and the pH optima for the formation of cysteine were determined to pH 8.0, pH 8.0, and pH 7.0, respectively. The purified recombinant OAS-TL proteins also catalysed the formation of hydrogen sulfide (H2S) and β-cyanoalanine from cysteine in the presence of dithiothreitol or KCN, respectively. The three isoenzymes differed in their Km for cysteine in the presence of dithiothreitol, but the Km for cysteine in the presence of KCN were almost identical. On a molar basis, the formation of H2S or cysteine by the OAS-TL proteins varied in relation to pH. For the determination of both enzyme activities, cysteine synthesis and cysteine desulfuration, in different compartments of plant cells, chloroplasts and mitochondria were isolated from Arabidopsis plants and the OAS-TL and L-cysteine desulfhydrase activities were determined. In conclusion, a) the evolution of H2S from higher plants originates from different enzyme reactions, and b) the side reactions of the OAS-TL proteins seem to contribute massively to the total H2S release of higher plants at least at higher pH values.
Keywords
- Arabidopsis thaliana, Cysteine, Desulfhydrase, Sulfide, β-cyanoalanine
ASJC Scopus subject areas
- Biochemistry, Genetics and Molecular Biology(all)
- Physiology
- Agricultural and Biological Sciences(all)
- Agronomy and Crop Science
- Agricultural and Biological Sciences(all)
- Plant Science
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In: Journal of plant physiology, Vol. 159, No. 2, 01.01.2002, p. 111-119.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Three O-acetyl-L-serine(thiol)lyase isoenzymes from Arabidopsis catalyse cysteine synthesis and cysteine desulfuration at different pH values
AU - Burandt, Petra
AU - Schmidt, Ahlert
AU - Papenbrock, Jutta
N1 - Funding information:. The expert technical assistance of Pamela von Trzebiatowski is gratefully acknowledged. We thank PD Dr. R. Hell for providing purified OAS-TL C protein used in initial experiments, Dr. H. Hesse for sending us pCS-A, pCS-B and pCS-C cDNA clones and Dr. J. Meens for sequencing work. For the lessons in isolating organelles from Arabidopsis we would like to thank Prof. Dr. H.-P. Braun and Wolf Wehrhan. The work was financially supported by grants from the Deutsche Forschungsgemeinschaft (PA 764/1-1/2, SCH 307/15-1).
PY - 2002/1/1
Y1 - 2002/1/1
N2 - So far, 7 different genes of the β-substituted alanine synthase family coding for proteins with O-acetyl-L-serine(thiol)lyase activity (OAS-TL) have been identified in Arabidopsis. The differences with respect to function and regulation of these isoforms are not well understood. In the present work, we aimed to differentiate between three OAS-TL proteins, A, B, and C, which are presumably localized in the cytoplasm, in plastids, and in mitochondria, respectively. The mature proteins were expressed in E. coli and the pH optima for the formation of cysteine were determined to pH 8.0, pH 8.0, and pH 7.0, respectively. The purified recombinant OAS-TL proteins also catalysed the formation of hydrogen sulfide (H2S) and β-cyanoalanine from cysteine in the presence of dithiothreitol or KCN, respectively. The three isoenzymes differed in their Km for cysteine in the presence of dithiothreitol, but the Km for cysteine in the presence of KCN were almost identical. On a molar basis, the formation of H2S or cysteine by the OAS-TL proteins varied in relation to pH. For the determination of both enzyme activities, cysteine synthesis and cysteine desulfuration, in different compartments of plant cells, chloroplasts and mitochondria were isolated from Arabidopsis plants and the OAS-TL and L-cysteine desulfhydrase activities were determined. In conclusion, a) the evolution of H2S from higher plants originates from different enzyme reactions, and b) the side reactions of the OAS-TL proteins seem to contribute massively to the total H2S release of higher plants at least at higher pH values.
AB - So far, 7 different genes of the β-substituted alanine synthase family coding for proteins with O-acetyl-L-serine(thiol)lyase activity (OAS-TL) have been identified in Arabidopsis. The differences with respect to function and regulation of these isoforms are not well understood. In the present work, we aimed to differentiate between three OAS-TL proteins, A, B, and C, which are presumably localized in the cytoplasm, in plastids, and in mitochondria, respectively. The mature proteins were expressed in E. coli and the pH optima for the formation of cysteine were determined to pH 8.0, pH 8.0, and pH 7.0, respectively. The purified recombinant OAS-TL proteins also catalysed the formation of hydrogen sulfide (H2S) and β-cyanoalanine from cysteine in the presence of dithiothreitol or KCN, respectively. The three isoenzymes differed in their Km for cysteine in the presence of dithiothreitol, but the Km for cysteine in the presence of KCN were almost identical. On a molar basis, the formation of H2S or cysteine by the OAS-TL proteins varied in relation to pH. For the determination of both enzyme activities, cysteine synthesis and cysteine desulfuration, in different compartments of plant cells, chloroplasts and mitochondria were isolated from Arabidopsis plants and the OAS-TL and L-cysteine desulfhydrase activities were determined. In conclusion, a) the evolution of H2S from higher plants originates from different enzyme reactions, and b) the side reactions of the OAS-TL proteins seem to contribute massively to the total H2S release of higher plants at least at higher pH values.
KW - Arabidopsis thaliana
KW - Cysteine
KW - Desulfhydrase
KW - Sulfide
KW - β-cyanoalanine
UR - http://www.scopus.com/inward/record.url?scp=0036194827&partnerID=8YFLogxK
U2 - 10.1078/0176-1617-00611
DO - 10.1078/0176-1617-00611
M3 - Article
AN - SCOPUS:0036194827
VL - 159
SP - 111
EP - 119
JO - Journal of plant physiology
JF - Journal of plant physiology
SN - 0176-1617
IS - 2
ER -