Li Zhong-Guang
School of Life Sciences, Engineering Research Center of Sustainable Development, Utilization of Biomass Energy Ministry of Education, Key Laboratory of Biomass Energy, Environmental Biotechnology Yunnan Province, Yunnan Normal University, Kunming, Yunnan, PR China.
Methods Enzymol. 2015;555:253-69. doi: 10.1016/bs.mie.2014.11.035. Epub 2015 Jan 8.
Hydrogen sulfide (H2S) which is considered as a novel gasotransmitter after reactive oxygen species and nitric oxide in plants has dual character, that is, toxicity that inhibits cytochrome oxidase at high concentration and as signal molecule which is involved in plant growth, development, and the acquisition of tolerance to adverse environments such as extreme temperature, drought, salt, and heavy metal stress at low concentration. Therefore, H2S homeostasis is very important in plant cells. The level of H2S in plant cells is regulated by its synthetic and degradative enzymes, L-/D-cysteine desulfhydrase (L-/D-DES), sulfite reductase (SiR), and cyanoalanine synthase (CAS), which are responsible for H2S synthesis, while cysteine synthase (CS) takes charge of the degradation of H2S, but its reverse reaction also can produce H2S. Here, after crude enzyme is extracted from plant tissues, the activities of L-/D-DES, SiR, CAS, and CS are measured by spectrophotometry, the aim is to further understand homeostasis of H2S in plant cells and its potential mechanisms.
硫化氢（H₂S）在植物中被认为是继活性氧和一氧化氮之后的一种新型气体信号分子，具有双重特性，即在高浓度时抑制细胞色素氧化酶的毒性以及在低浓度时作为参与植物生长、发育以及对极端温度、干旱、盐和重金属胁迫等逆境耐受性获得的信号分子。因此，H₂S稳态在植物细胞中非常重要。植物细胞中H₂S的水平由其合成和降解酶L-/D-半胱氨酸脱硫酶（L-/D-DES）、亚硫酸盐还原酶（SiR）和氰丙氨酸合酶（CAS）调节，这些酶负责H₂S的合成，而半胱氨酸合酶（CS）负责H₂S的降解，但其逆反应也能产生H₂S。在此，从植物组织中提取粗酶后，通过分光光度法测定L-/D-DES、SiR、CAS和CS的活性，目的是进一步了解植物细胞中H₂S的稳态及其潜在机制。
