Purification and biochemical characterization of a β-cyanoalanine synthase expressed in germinating seeds of Sorghum bicolor (L.) moench
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Date
2018-02-06
Journal Title
Journal ISSN
Volume Title
Publisher
De Gruyter : Turkish Journal of Biochemistry
Abstract
Background: β-Cyanoalanine synthase plays essential
roles in germinating seeds, such as in cyanide homeostasis.
Methods: β-Cyanoalanine synthase was isolated from
sorghum seeds, purified using chromatographic techniques
and its biochemical and catalytic properties were
determined.
Results: The purified enzyme had a yield of 61.74% and
specific activity of 577.50 nmol H2S/min/mg of protein.
The apparent and subunit molecular weight for purified
β-cyanoalanine synthase were 58.26 ± 2.41 kDa
and 63.4 kDa, respectively. The kinetic parameters
with sodium cyanide as substrate were 0.67 ± 0.08 mM,
17.60 ± 0.50 nmol H2S/mL/min, 2.97 × 10−1 s−1 and 4.43 × 102
M−1 s−1 for KM, Vmax, kcat and kcat/KM, respectively. With
L-cysteine as substrate, the kinetic parameters were
2.64 ± 0.37 mM, 63.41 ± 4.04 nmol H2S/mL/min, 10.71 × 10−1
s−1 and 4.06 × 102 M−1 s−1 for KM, Vmax, kcat and kcat/KM, respectively.
The optimum temperature and pH for activity were
35°C and 8.5, respectively. The enzyme retained more than half of its activity at 40°C. Inhibitors such as HgCl2, EDTA,
glycine and iodoacetamide reduced enzyme activity.
Conclusion: The biochemical properties of β-cyanoalanine
synthase in germinating sorghum seeds highlights its
roles in maintaining cyanide homeostasis
Description
Staff Publication
Keywords
β-Cyanoalanine synthase;, Cyanide;, Sorghum;, Detoxification;, Characterization;, Purification.
Citation
Amiola, R.O., Ademakinwa, A.N., Ayinla, Z.A., Ezima, E.N., & Agboola, F. (2018). Purification and biochemical characterization of a β-cyanoalanine synthase expressed in germinating seeds of Sorghum bicolor (L.) moench. Turkish Journal of Biochemistry, 43, 638 - 650. https://doi.org/10.1515/tjb-2017-0214