MEMBRANE GLYCOPROTEIN CHANGES DURING DIFFERENTIATION

雌激素诱导鸡输卵管分化过程中的变化 膜制剂中多羟基磷酸(Dol-P)和多氯酚激酶的水平 似乎在增加。调节DOL-P水平的机制将是 学习。因此，我们计划研究与DOL-P有关的异丙烯基转移酶 焦磷酸法尼基和焦磷酸异戊烯的合成 对酶的性质及其可能的调节作用 差异化。Dol-P的α-异戊二烯单元比还原 将会被研究。我们还将研究可能涉及到的其他酶 多种多元醇衍生物的相互转化；DOL-P磷酸酶， 多巴胆碱：磷脂酰胆碱转酰基酶和脂肪酰胆碱转酰基酶。 输卵管组织切片将与放射性甲氧戊酸和醋酸盐孵育 测定不同二苯二醇衍生物的合成速率和 胆固醇在输卵管分化和萎缩过程中的作用。这些 研究还将使我们能够衡量DOL-P的周转率和分布 在它的各种新陈代谢形式中。 将研究脂质中间途径的各个步骤的变化。 将放射性脂质中间体外源添加到膜制剂中。 脂连接低聚糖、葡萄糖苷酶和甘露糖苷酶的组装 参与低聚糖加工是本研究的主题。 参与合成“复合”糖蛋白的糖基转移酶也将 被研究。将制备特定的糖蛋白底物并转移 来自糖核苷酸的糖将被检测。 输卵管含有β-N-乙酰氨基葡萄糖苷酶和蛋清两种同工酶 含有一种可能与其中一种输卵管同工酶相同的形式。这个 它们之间的结构关系和可能的生物合成关系 同工酶将被研究。这些研究可能会揭示一些深刻的差异 胞内同工酶和分泌同工酶之间。

During the course of estrogen induced chick oviduct differentiation dolichylphosphate (Dol-P) and dolichol kinase levels in membrane preparations appear to increase. The mechanisms by which Dol-P levels are modulated will be studied. Thus, we plan to study the prenyl transferases involved in Dol-P synthesis from farnesyl pyrophosphate and isopentenyl pyrophosphate with respect to the properties of the enzyme and its possible regulation during differentiation. The specific reduction of the alpha-isoprene unit of Dol-P will be studied. We will also study other enzymes that may be involved in the interconversion of various dolichol derivatives; Dol-P phosphatase, dolichol:phosphatidylcholine transacylase and fatty acyl dolichol acylase. Oviduct tissue slices will be incubated with radioactive mevalonate and acetate to determine the rates of synthesis of various dolichol derivatives and cholesterol during the course of oviduct differentiation and atrophy. These studies will also allow us to measure the turnover of Dol-P and the distribution of dolichol amongst its various metabolic forms. Changes in individual steps of the lipid intermediate pathway will be studied with radioactive lipid intermediates added exogenously to membrane preparations. Assembly of the lipid-linked-oligosaccharide, the glucosidases and mannosidases involved in oligosaccharide processing are the topics for this study. Glycosyl transferases involved in synthesizing "complex" glycoproteins will also be studied. Specific glycoprotein substrates will be prepared and transfer of sugar from sugar nucleotides will be assayed. The oviduct contains two isozymes of beta-N-acetylglucosamidase and egg white contains one form that may be identical to one of the oviduct isozymes. The structural relationships and possible biosynthetic relationship between these isozymes will be studied. These studies may reveal some profound differences between intracellular and secreted isozymes.