Subcellular and Developmental Distribution of beta-Cyanoalanine Synthase in Barley Leaves.
Subcellular and Developmental Distribution of beta-Cyanoalanine Synthase in Barley Leaves.
复制标题
大麦叶中β-氰基丙氨酸合酶的亚细胞和发育分布。
DOI：
10.1104/pp.78.2.285
复制
发表时间：
1985
期刊：
影响因子：
7.4
通讯作者：
E. Conn
中科院分区：
文献类型：
--
作者：
E. Wurtele;B. Nikolau;E. Conn
研究了大麦叶片中β-氰丙氨酸合成酶（EC 4.4.1.9）的亚细胞和发育分布。总叶活性为1.1微摩尔/分钟/克鲜重。大麦叶肉原生质体裂解的蔗糖密度梯度揭示了β-氰基丙氨酸合酶在线粒体中的独特或主要定位。液泡和叶绿体中均不存在β-氰丙氨酸合酶，其活性分布于大麦叶的全长。活动是依赖于发展阶段，在最古老的（顶端）与最年轻的（基础）部分的叶的活性高3.5倍。从这些部分分离的叶肉原生质体的活性的相应差异是7.5倍。在较年轻的叶seagments，非叶绿素组织占总β-氰丙氨酸合酶活性的70%。这些结果进行了讨论，参考HCN作为底物在大麦叶中的形成。
The subcellular and developmental distribution of beta-cyanoalanine synthase (EC 4.4.1.9), which catalyzes the reaction between cysteine and HCN to form beta-cyanoalanine and H(2)S, were investigated in barley (Hordeum vulgare) leaves. Total leaf activity was 1.1 micromoles per minute per gram fresh weight. Sucrose density gradients of lysed mesophyll protoplasts of barley revealed the exclusive or predominant localization of beta-cyanoalanine synthase in the mitochondria. The enzyme was absent from both vacuole and chloroplast fractions.beta-Cyanoalanine synthase activity was distributed over the entire length of the barley leaf. Activity was dependent on the developmental stage, with a 3.5-fold higher activity in the oldest (apical) compared to the youngest (basal) parts of the leaf. The corresponding difference in activity for mesophyll protoplasts isolated from these parts was 7.5-fold. In younger leaf seagments, the nonchlorophyllous tissues accounted for up to 70% of the total beta-cyanoalanine synthase activity. These results are discussed with reference to the formation of HCN as a substrate in barley leaves.