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.
