LOCALIZATION OF ATP SULFURYLASE AND O-ACETYLSERINE(THIOL)LYASE IN SPINACH LEAVES
LOCALIZATION OF ATP SULFURYLASE AND O-ACETYLSERINE(THIOL)LYASE IN SPINACH LEAVES
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DOI：
10.1104/pp.94.3.1345
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发表时间：
1990-11-01
期刊：
影响因子：
7.4
通讯作者：
DOUCE, R
中科院分区：
文献类型：
--
作者：
LUNN, JE;DROUX, M;DOUCE, R
菠菜(Spinacia HolaceaL.)细胞内ATP硫酰化酶和乙酰丝氨酸(硫醇)裂解酶的区隔作用通过细胞器的分离和原生质体的分离来研究叶片。ATP硫酰基酶主要位于叶绿体中，但也存在于细胞质中。未发现线粒体中存在三磷酸腺苷硫酰基酶活性的证据。用阴离子交换层析分离得到两种形式的三磷酸腺苷硫酰基酶。O-乙酰丝氨酸(硫醇)裂解酶活性主要存在于叶绿体和胞浆中，但也存在于线粒体中。用阴离子交换层析分离了三种形式的乙酰丝氨酸(硫醇)裂解酶，每一种形式都专属于细胞内的一个隔室。由于反应的平衡常数不佳，以及胞质中存在微摩尔浓度的无机焦磷酸盐，胞浆中的ATP硫酰基酶可能不是活体活性的，因此它的作用尚不清楚。这表明植物细胞可能不能在不同的隔室之间运输半胱氨酸，因此蛋白质合成所需的半胱氨酸必须在原位合成，因此在合成蛋白质的三个隔室中存在o-乙酰丝氨酸(硫醇)裂解酶。
The intracellular compartmentation of ATP sulfurylase andO-acetylserine(thiol)lyase in spinach (Spinacia oleraceaL.) leaves has been investigated by isolation of organelles and fractionation of protoplasts. ATP sulfurylase is located predominantly in the chloroplasts, but is also present in the cytosol. No evidence was found for ATP sulfurylase activity in the mitochondria. Two forms of ATP sulfurylase were separated by anion-exchange chromatography. The more abundant form is present in the chloroplasts, the second is cytosolic.O-Acetylserine(thiol)lyase activity is located primarily in the chloroplasts and cytosol, but is also present in the mitochondria. Three forms ofO-acetylserine(thiol)lyase were separated by anion-exchange chromatography, and each was found to be specific to one intracellular compartment. The cytosolic ATP sulfurylase may not be activein vivodue to the unfavorable equilibrium constant of the reaction, and the presence of micromolar concentrations of inorganic pyrophosphate in the cytosol, therefore its role remains unknown. It is suggested that the plant cell may be unable to transport cysteine between the different compartments, so that the cysteine required for protein synthesis must be synthesizedin situ, hence the presence ofO-acetylserine(thiol)lyase in the three compartments where proteins are synthesized.