%0 Journal Article %T Five Decades with Polyunsaturated Fatty Acids: Chemical Synthesis, Enzymatic Formation, Lipid Peroxidation and Its Biological Effects %A Angel Catal¨¢ %J Journal of Lipids %D 2013 %I Hindawi Publishing Corporation %R 10.1155/2013/710290 %X I have been involved in research on polyunsaturated fatty acids since 1964 and this review is intended to cover some of the most important aspects of this work. Polyunsaturated fatty acids have followed me during my whole scientific career and I have published a number of studies concerned with different aspects of them such as chemical synthesis, enzymatic formation, metabolism, transport, physical, chemical, and catalytic properties of a reconstructed desaturase system in liposomes, lipid peroxidation, and their effects. The first project I became involved in was the organic synthesis of [1-14C] eicosa-11,14-dienoic acid, with the aim of demonstrating the participation of that compound as a possible intermediary in the biosynthesis of arachidonic acid ¡°in vivo.¡± From 1966 to 1982, I was involved in several projects that study the metabolism of polyunsaturated fatty acids. In the eighties, we studied fatty acid binding protein. From 1990 up to now, our laboratory has been interested in the lipid peroxidation of biological membranes from various tissues and different species as well as liposomes prepared with phospholipids rich in PUFAs. We tested the effect of many antioxidants such as alpha tocopherol, vitamin A, melatonin and its structural analogues, and conjugated linoleic acid, among others. 1. Introduction Five decades ago PUFAs were of negligible interest, for their only value was as constituents of drying oils. They were known to be components of nutritional fats but were considered to be functional only as a source of calories. In 1929, Burr and his wife, Mildred, published a paper [1] in which they discovered that elimination of fat from the diet of animals induced a deficiency illness, and their afterward papers showed that this illness could be prevented or cured by the addition of linoleic acid in the diet [2, 3]. Thus, they proved convincingly that linoleic acid was an essential fatty acid and introduced the concept that fats should no longer be considered just as a source of calories and as a carrier of fat-soluble vitamins, but that fats have an intrinsic specific nutritive value. Much more would be discovered later about the functions of the essential fatty acids. My first experience with polyunsaturated fatty acids started in 1964 when I was accepted as ¡°Research Assistant¡± without salary at the C¨¢tedra de Bioqu¨ªmica, Instituto de Fisiolog¨ªa, Facultad de Ciencias M¨¦dicas, Universidad Nacional de La Plata, Argentina. This was before the era of molecular biology and the limitations in biochemical science were organic and analytical %U http://www.hindawi.com/journals/jl/2013/710290/