Department of Biochemistry and Biophysics, University of California, Davis, California 95616.
Plant Physiol. 1979 Aug;64(2):187-92. doi: 10.1104/pp.64.2.187.
The subcellular localization of the starch biosynthetic and degradative enzymes of spinach leaves was carried out by measuring the distribution of the enzymes in a crude chloroplast pellet and soluble protein fraction, and by the separation on sucrose density gradients of intact organelles, chloroplasts, peroxisomes, and mitochondria of a protoplast lysate. ADP-Glucose pyrophosphorylase, starch synthase, and starch-branching enzymes are quantitatively associated with the chloroplasts. The starch degradative enzymes amylase, R-enzyme (debranching activity), phosphorylase, and D-enzyme (transglycosylase) are observed both in the chloroplast and soluble protein fractions, the bulk of the degradative enzyme activities reside in the latter fraction. Chromatography of a chloroplast extract on diethylaminoethyl-cellulose resolves the R- and D-enzymes from amylase and phosphorylase activities although the two latter enzyme activities coeluted. The digestion pattern of amylase with amylopectin as a substrate indicates an endolytic activity but displays properties unlike the typical alpha-amylase as isolated from endosperm tissue.
通过测量酶在粗叶绿体颗粒和可溶性蛋白部分中的分布，以及通过蔗糖密度梯度分离完整细胞器、叶绿体、过氧化物酶体和原生质体裂解物中的线粒体，对菠菜叶片的淀粉生物合成和降解酶的亚细胞定位进行了研究。ADP-葡萄糖焦磷酸化酶、淀粉合酶和淀粉分支酶与叶绿体定量相关。淀粉酶、R 酶（分支活性）、磷酸化酶和 D 酶（转移酶）等淀粉降解酶既存在于叶绿体中，也存在于可溶性蛋白部分，大部分降解酶活性存在于后者部分。尽管后两种酶活性共同洗脱，但叶绿体提取物在二乙氨基乙基纤维素上的层析将 R 酶和 D 酶与淀粉酶和磷酸化酶活性分开。以支链淀粉为底物的淀粉酶消化模式表明其具有内切酶活性，但表现出不同于从胚乳组织中分离出的典型α-淀粉酶的特性。
