矮牵牛花中花色苷甲基转移酶的亚细胞定位。
Subcellular Localization of Anthocyanin Methyltransferase in Flowers of Petunia hybrida.
机构信息
Department of Plant Physiology, University of Amsterdam, Kruislaan 318, 1098 SM Amsterdam, The Netherlands.
出版信息
Plant Physiol. 1983 Jun;72(2):287-90. doi: 10.1104/pp.72.2.287.
The subcellular localization of the enzyme anthocyanin-methyltransferase was studied in cells (protoplasts) obtained from the upper epidermis of petals of Petunia hybrida Hort. Vacuoles were isolated from protoplasts to ascertain the possible presence of the enzyme in these organelles. The recovery of methyltransferase activity in vacuole-enriched fractions equalled that of the cytosolic marker enzyme glucose-6-phosphate dehydrogenase. The relative activity of methyltransferase in the vacuole fraction was one tenth of that in the protoplast. Neither whole protoplasts nor isolated vacuoles contained inhibitors of methyltransferase activity. Examination of fractions obtained by differential centrifugation of a protoplast lysate showed that the major part of the methyltransferase activity was cytosolic. Activity found in a 130,000g pellet was due to nonspecific adhesion to membranes. The results indicate that terminal steps of anthocyanin biosynthesis take place in the cytosol. They do not lend support to the notion that the vacuole might be involved in (part of) this process.
研究了从矮牵牛杂种 Hort.的花瓣上表皮获得的细胞（原生质体）中酶花色素苷甲基转移酶的亚细胞定位。从原生质体中分离液泡，以确定该酶是否存在于这些细胞器中。富含液泡的级分中甲基转移酶活性的回收与胞质标记酶葡萄糖-6-磷酸脱氢酶的活性相等。甲基转移酶在液泡级分中的相对活性是原生质体的十分之一。完整的原生质体或分离的液泡均不含有甲基转移酶活性的抑制剂。用原生质体裂解物的差速离心获得的级分的检查表明，甲基转移酶的大部分活性是胞质的。在 130,000g 沉淀中发现的活性是由于与膜的非特异性粘附所致。结果表明，花色素苷生物合成的末端步骤发生在细胞质中。它们不支持液泡可能参与（部分）该过程的观点。
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