TY - JOUR
T1 - β-Cyanoalanine synthase and cysteine synthase from potato
T2 - Molecular cloning, biochemical characterization, and spatial and hormonal regulation
AU - Maruyama, Akiko
AU - Saito, Kazuki
AU - Ishizawa, Kimiharu
N1 - Funding Information:
We would like to thank Dr Ahlert Schmidt (Universität Hannover) for providing the antibody raised against spinach CAS. This work was supported, in part, by Grants-in-Aid for Scientific Research and the Japan Society for Promotion of Science (JSPS), by the Ministry of Education, Science, Sports and Culture, Japan (Monbusho), and by CREST of JST (Japan Science & Technology). A.M. is supported by a Research Fellowship from the Japan Society for the Promotion of Science for Young Scientists (Nos 1839 and 6340).
PY - 2001
Y1 - 2001
N2 - β-Cyanoalanine synthase (CAS, L-3-cyanoalanine synthase; EC 4.4.1.9) is the most important enzyme in cyanide metabolism. In addition to CAS, cysteine synthase (CS, EC 4.2.99.8) possesses CAS activity. To explore the physiological significance of cyanide metabolism, we isolated the cDNA clones corresponding to purified CAS (designated PCAS-1 and PCAS-2) and CS (designated PCS-1 and PCS-2) from potato using the information of these amino acid sequences. The recombinant proteins of PCS-1, PCS-2 and PCAS-1 catalyzed both CAS and CS reactions, although the ratios between CAS and CS activity were remarkably different. PCAS-1 preferred the substrates for the CAS reaction to the substrates for the CS reaction. From the kinetic characters and homology of amino acid sequences with known CS-like proteins, PCS-1, PCS-2 and PCAS-1 were identified as cytosolic CS, plastidic CS and mitochondrial CAS, respectively. The highest level of CAS activity, CAS protein and its mRNA were detected in potato buds. Stimulation of CAS activity and protein accumulation by ethylene without the concomitant increase of its mRNA suggested that ethylene induces CAS protein accumulation at the post-transcriptional level.
AB - β-Cyanoalanine synthase (CAS, L-3-cyanoalanine synthase; EC 4.4.1.9) is the most important enzyme in cyanide metabolism. In addition to CAS, cysteine synthase (CS, EC 4.2.99.8) possesses CAS activity. To explore the physiological significance of cyanide metabolism, we isolated the cDNA clones corresponding to purified CAS (designated PCAS-1 and PCAS-2) and CS (designated PCS-1 and PCS-2) from potato using the information of these amino acid sequences. The recombinant proteins of PCS-1, PCS-2 and PCAS-1 catalyzed both CAS and CS reactions, although the ratios between CAS and CS activity were remarkably different. PCAS-1 preferred the substrates for the CAS reaction to the substrates for the CS reaction. From the kinetic characters and homology of amino acid sequences with known CS-like proteins, PCS-1, PCS-2 and PCAS-1 were identified as cytosolic CS, plastidic CS and mitochondrial CAS, respectively. The highest level of CAS activity, CAS protein and its mRNA were detected in potato buds. Stimulation of CAS activity and protein accumulation by ethylene without the concomitant increase of its mRNA suggested that ethylene induces CAS protein accumulation at the post-transcriptional level.
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U2 - 10.1023/A:1011629703784
DO - 10.1023/A:1011629703784
M3 - Article
C2 - 11575729
AN - SCOPUS:0034807334
VL - 46
SP - 749
EP - 760
JO - Plant Molecular Biology
JF - Plant Molecular Biology
SN - 0167-4412
IS - 6
ER -