The objectives of this research are to make use of earlier studies on the synthesis and conformation of cyclopentanoid cyclitols by using these substances as the basis of studies on the relation of lipid structure to biological function. Most of the synthetic methods for these cyclitols were developed and standardized in this laboratory. Specific problems and areas to be attacked include the following: 1. Synthesis of pseudoglycerides, i.e. analogues of natural, glycerol- containing lipids: triglycerides, phosphatidic acids, choline- and ethanolamine-containing phospholipids, in which the glycerol backbone is replaced by one of the isomeric cyclopentane-1,2,3,-triols. Conformers of the cyclopentanetriols correspond to many possible rotamers of glycerol. 2. Biological and physical studies of the pseudoglycerides. When a sufficient number of the analogues are available they will be used as probes for determining the conformational specificity of lipases, phospholipases and other enzymes of lipid metabolism. The analogues will also be studied for their ability to enhance or depress lipid metabolism in cell cultures and eventually in animals. The relationship of the configuration of the backbone to the physical and biophysical properties of the analogues will be studied. Such matters as crystal packing, transition temperatures in crystals and bilayer membranes, properties of membrane vesicles prepared from the analogues of phospholipids with and without certain natural lipids will be investigated.