Inositol Metabolism In Plants

从长花百合成熟未发芽花粉中制备孢子体。将用于制备亚细胞花粉颗粒的悬浮液，该悬浮液可通过梯度密度离心分离得到“储存体”，即含有富含植酸的内含物的细胞器。这些细胞器的植酸酶含量将被研究，特别是pH 5和pH 8的植酸酶，它们已经从整个花粉中分离和部分纯化。每个植酸酶的活性将被纯化到均质性，并研究底物要求、产物形成、定位和可能的功能。从1l -肌醇-1- p形成植酸盐的问题将被检查，以确定1l -肌醇-1- p合成酶或肌醇激酶是从磷酸化的第一步负责。这将通过测量d -葡萄糖-6- p转化为1l -肌醇-1- p过程中C5处的氢同位素交换来完成，这一过程在之前的碳从d -葡萄糖-6- p转化为udp - d -葡萄糖酸盐和葡萄糖酸盐代谢的细胞壁产物的研究中成功地使用过。本研究的意义在于解释磷酸盐在调节植物代谢中的作用。植酸盐是一种至关重要的储磷化合物，但实际上我们对植物如何制造植酸盐一无所知。磷酸盐在碳水化合物代谢中起着重要的调节作用，从而决定植物的生产力

Sporoplasts prepared from mature ungerminated pollen of Lilium longiflorum Thunb. will be used to prepare a suspension of subcellular pollen particles which can be fractionated by gradient density centrifugation to yield "storage bodies", organelles bearing phytin-rich inclusions. These organelles will be studied for their phytase content, notably pH 5 and pH 8 phytases, which have already been isolated and partially purified from whole pollen. Each phytase activity will be purified to homogeniety and studied with regard to substrate requirements, products formed, localization, and possible functions. The question of phytate formation from 1L-myo-inositol-1-P will be examined to determine whether 1L-myo-inositol-1-P synthase or myo- inositol kinase is responsible from the first step of phosphorylation. This will be done by measuring hydrogen isotope exchange at C5 of D-glucose-6-P during its conversion to 1L-myo-inositol-1-P, a procedure used successfully in previous studies of the path of carbon from D-glucose-6-P to UDP-D-glucoronate and cell wall products of glucoronate metabolism. The significance of this research is explaining the role of phosphate in regulating plant metabolism. Phytate is a phosphorus storage compound of crucial importance yet practically nothing is known of how it is made by the plant. Phosphates play important regulatory roles in carbohydrate metabolism which in turn determines plant productivity.***//